Grand Underground

The Grand Underground (Japanese: Grand Underground Cave) is an area in found beneath the entire Sinnoh region. Players can travel to the Grand Underground using an Explorer Kit, given to the player by the Underground Man in Eterna City.
It takes the place of the Underground from .
==Changes from Diamond and Pearl==
* The map is still split into six disjoint areas like the original Underground, but the sizes and locations of the six areas do not match those of the original Underground.
* Areas now include Pokémon Hideaways, and each area now corresponds to a different aesthetic environment.
* The digging minigame returns following closely to its original incarnation with the exception of digging up Pokémon statues, which come from Stone Boxes. 
** If the player runs out of digging spots, more will appear once the player enters and exits a Hideaway.
** As of the version 1.1.0 update, after the Sinnoh Pokédex is completed, Mysterious Shard S and Mysterious Shard L will start appearing in the underground for use in Ramanas Park.
* Secret Bases return and are created using a Digger Drill as before.
** Bases can only be decorated with statues and pedestals to place them on.
** The flag stealing mechanic has been removed.
* Goods and Traps, with the sole exception of the Digger Drill, have been removed.
* Spheres no longer have a numerical size and are instead categorized as Small or Large. They can no longer be buried either.
* Instead of goods or traps, merchants (who appear as s) in the Grand Underground can exchange treasures and for spheres. Spheres can now be exchanged for pedestals, items, and TMs.
** Some Hikers found in the Grand Underground allow the player to rest, acting as a Pokémon Center.
* The radar is now triggered by pressing [R] and searches the area around the player's location.
* The Grand Underground supports online communication, compared to the original games which only supported local communication.
* Steps taken in the Grand Underground count towards distance as well as the step counter app.
* and will occasionally pop out and leave pink sparkles that give 1 and 3 points respectively, and accumulating 40 of these points causes "something good to happen". This results in a variety of special effects lasting for a period of 4 minutes, which begins and ends when a whistle is heard:
** The odds to encounter a Shiny Pokémon in Hideaways is raised from 1/4096 to 1/2048.
** All Stone Boxes found while digging will be Gorgeous Stone Boxes. 
** The progress gauge and bonus period is shared between all players connected to the same instance of the Grand Underground. If all connected players leave the Grand Underground, this gauge resets to zero.
==Zones==
The Grand Underground is organized into six zones, with each zone containing Pokémon Hideaways. 
North-western	East and West	North-eastern
 	 	
South-western	Central 	South-eastern
 	 	
===Pokémon Hideaways===
Pokémon Hideaways (Japanese: ポケモンのれ Pokémon Hideaway) are new places where wild Pokémon can be encountered. Unlike the main overworld, these areas feature symbol encounters. Each of the six areas contain at least one large Hideaway (known as Caverns), and multiple, smaller Hideaways (known as Caves) scattered throughout the map. Various hideaways - particularly larger areas - include items for Trainers to discover. 
Dazzling Cave 	Fountainspring Cave	Grassland Cave	Icy Cave
 	 	 	
Riverbank Cave	Rocky Cave 	Sandsear Cave 	Spacious Cave
 	 	 	
Swampy Cave 	Volcanic Cave 	Whiteout Cave 	
 	 	 	
Big Bluff Cavern 	Bogsunk Cavern	Glacial Cavern	Stargleam Cavern
 	 	 	
Still-Water Cavern	Sunlit Cavern 	Typhlo Cavern 	
 	 	 	
After the player fulfills the following objectives during their adventure, another group of Pokémon are added to the pool of possible encounters, with some requiring Surf in order to access:
* Obtaining 
* Obtaining 
* Earning the 
* Obtaining 
* Obtaining the National Pokédex
With each additional badge earned by the player, the levels of wild Pokémon are increased.
Progression 	Level Ranges
1 Badge 	16-20
2 Badges 	25-29
3 Badges 	29-33
4 Badges 	33-37
5 Badges 	36-40
6 Badges 	39-43
7 Badges 	42-46
8 Badges 	50-55
Elite Four defeated	58-63
Additionally, all Pokémon in the Hideaways will have at least one Egg Move if applicable, unlocking some Egg Moves that would otherwise be unobtainable, e.g. for .
==Item appearances==
When mining, there is a chance for an item to be found in a bulging wall. Some items have requirements to appear, such as Mysterious Shards, only found after obtaining the National Pokedex and fossils of Pokémon not native to Sinnoh, which can only be found after defeating or capturing or .
 	 	 	
Red Shard 	Blue Shard 	Green Shard 	Yellow Shard
 	 	 	
Helix Fossil	Dome Fossil 	Old Amber 	Root Fossil
 	 	 	
Claw Fossil 	Armor Fossil 	Skull Fossil 	Rare Bone
 	 	 	
Star Piece 	Revive 	Max Revive 	Iron Ball
 	 	 	
Heart Scale 	Light Clay 	Odd Keystone 	Hard Stone
 	 	 	
Fire Stone 	Water Stone 	Thunder Stone 	Leaf Stone
 	 	 	
Moon Stone 	Sun Stone 	Oval Stone 	Everstone
 	 	 	
Smooth Rock 	Heat Rock 	Icy Rock 	Damp Rock
 	 	 	
Draco Plate 	Dread Plate 	Earth Plate 	Fist Plate
 	 	 	
Flame Plate 	Icicle Plate 	Insect Plate 	Iron Plate
 	 	 	
Meadow Plate	Mind Plate 	Sky Plate 	Splash Plate
 	 	 	
Spooky Plate	Stone Plate 	Toxic Plate 	Zap Plate
 	 	 	
Pixie Plate 	Mysterious Shard S	Mysterious Shard L	
==Pokémon Statues==
Much like Spheres and Fossils, Stone Boxes associated with each Pokémon type can be found by digging. There are two kinds, the commonly seen Pretty Stone Boxes and the rarer Gorgeous Stone Boxes, which give the player Standard Statues and Color Statues respectively.
When placed in a player's Secret Base, the chance of seeing a Pokémon of the corresponding type in Hideaways increases. Only the type with the greatest number of statues of the corresponding type will have a boosted effect, which is indicated by the color of the orb placed next to the entrance of the player's base. This "Statue Effect" is increased for every statue of that type that is placed in the player's Secret Base. If the Pokémon has two types, the primary type of the Pokémon has a greater effect than its secondary type in determining which type has a boosted effect. Hence, if only one statue of a dual-typed Pokémon is placed, the boosted type will correspond to the Pokémon's primary type. Furthermore, larger statues of any type provide a greater effect. A maximum of 18 statues can be placed at one time.
Catching a Legendary Pokémon in Ramanas Park will reward the player with a statue of that Pokémon for their Secret Base. These Statues cannot be found normally whilst digging underground.
A player's chance of finding a Gorgeous Stone Box can be temporarily increased for four minutes by collecting 40 that can be found scattered throughout the Grand Underground. Each Diglett counts as one towards the tally, while encountering a counts as three. This count is reset when the player leaves the Grand Underground. 
===List of Stone Boxes===
Stone Box									
Pretty 									
Gorgeous 									
Stone Box									
Pretty 									
Gorgeous 									
==Secret Base==
Similar to , the player is able to create a Secret Base within the Grand Underground using a Digger Drill. However, unlike the previous games, the Secret Base can only be decorated with statues and pedestals to place them on. The size of a Secret Base can be expanded by exchanging spheres with one of the merchants in the Grand Underground. Like in the original, a player can only have a single base at a time.
===List of pedestals===
Statues can be placed on pedestals. These pedestals can be exchanged from merchants in the Grand Underground. Certain pedestals can also be purchased at the Veilstone Department Store, and also received from the Underground Man as a reward for completing certain tasks.
Size	Square Pedestal	Round Pedestal	Sturdy Pedestal	Clear Pedestal	Spin Pedestal	Spinback Pedestal	Dawn Pedestal	Night Pedestal	Diamond Pedestal	Pearl Pedestal
XS 	 	 	 	 	 	 	— 	— 	— 	—
S 	 	— 	 	 	— 	— 	— 	— 	— 	—
M 	 	 	 	 	 	 	— 	— 	— 	—
L 	 	 	 	 	 	 	 	 	 	
XL 	 	 	 	 	 	 	 	 	 	
==Merchants==
Spheres can be used to exchange for pedestals and various items, such as TMs. There are three types of merchants in the Grand Underground:
* Small sphere merchants allow the player to purchase additional Digger Drills, small or medium pedestals, and TMs which change daily.
* Large sphere merchants who offer large or extra large pedestals, and a different set of TMs.
* An item exchange merchant, who will give spheres in exchange for items that can be dug out. Additionally, he can also be paid to expand the player's Secret Base.
===Small sphere merchant===
Item 	Cost 	Days available
Digger Drill 	×8 or 10×8 or 10×8 or 10 	Always, after receiving a Digger Drill from the Underground Man
Red Sphere L 	×50 or 55 	One random choice each day
Green Sphere L 	×50 or 55 	One random choice each day
Blue Sphere L 	×50 or 55 	One random choice each day
Prism Sphere L 	×50 or 55 	One random choice each day
Pale Sphere L 	×50 or 55 	One random choice each day
Square Pedestal XS 	×10 or 15×10 or 15×10 or 15 	Monday, Friday, Sunday
Square Pedestal S 	×15 or 20×15 or 20×15 or 20 	Monday, Sunday
Square Pedestal M 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Monday, Saturday, Sunday
Sturdy Pedestal XS 	×10 or 15×10 or 15×10 or 15 	Wednesday, Friday, Sunday
Sturdy Pedestal S 	×15 or 20×15 or 20×15 or 20 	Wednesday, Sunday
Sturdy Pedestal M 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Wednesday, Saturday, Sunday
Round Pedestal XS 	×10 or 15×10 or 15×10 or 15 	Tuesday, Friday, Sunday
Round Pedestal M 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Tuesday, Saturday, Sunday
Clear Pedestal XS 	×10 or 15×10 or 15×10 or 15 	Thursday, Friday, Sunday
Clear Pedestal S 	×15 or 20×15 or 20×15 or 20 	Thursday, Sunday
Clear Pedestal M 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Thursday, Saturday, Sunday
Spin Pedestal XS 	×25 or 30×25 or 30×25 or 30×12 or 15/8 or 10×8 or 10/12 or 15 	Monday, Tuesday, Wednesday, Friday, Sunday
Spinback Pedestal XS	×25 or 30×25 or 30×25 or 30×12 or 15/8 or 10×8 or 10/12 or 15 	Tuesday, Thursday, Saturday, Sunday
TM01 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM03 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM04 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM06 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM08 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM09 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM12 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM23 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM34 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM41 	×10 or 13×10 or 13×10 or 13×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM45 	×10 or 13×10 or 13×10 or 13×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM46 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM47 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM48 	×10 or 13×10 or 13×10 or 13×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM49 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM55 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM56 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM57 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM60 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM61 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM62 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM63 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM65 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM66 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM67 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM69 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM72 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM73 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM76 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM77 	×10 or 13×10 or 13×10 or 13×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM81 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM82 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM85 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM86 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM87 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM88 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM91 	×20 or 22×20 or 22×20 or 22×13 or 15/10 or 13×10 or 13/13 or 15	Random selection of TMs each day
TM92 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM93 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM94 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM96 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM97 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM98 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM100 	×15 or 18×15 or 18×15 or 18×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
 	 	Random selection of TMs each day
===Large sphere merchant===
Item 	Cost 	Days available
Red Sphere S×40 	×2 or 3 	One random choice each day
Green Sphere S×40 	×2 or 3 	One random choice each day
Blue Sphere S×40 	×2 or 3 	One random choice each day
Prism Sphere S×40 	×2 or 3 	One random choice each day
Pale Sphere S×40 	×2 or 3 	One random choice each day
Square Pedestal L 	×10 or 15×10 or 15×10 or 15×5 or 7/3 or 5×3 or 5/5 or 7 	Monday, Friday, Sunday
Square Pedestal XL 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Monday, Saturday, Sunday
Sturdy Pedestal L 	×10 or 15×10 or 15×10 or 15×5 or 7/3 or 5×3 or 5/5 or 7 	Wednesday, Friday, Sunday
Sturdy Pedestal XL 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Wednesday, Saturday, Sunday
Round Pedestal L 	×10 or 15×10 or 15×10 or 15×5 or 7/3 or 5×3 or 5/5 or 7 	Tuesday, Friday, Sunday
Round Pedestal XL 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Tuesday, Saturday, Sunday
Clear Pedestal L 	×10 or 15×10 or 15×10 or 15×5 or 7/3 or 5×3 or 5/5 or 7 	Thursday, Friday, Sunday
Clear Pedestal XL 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Thursday, Saturday, Sunday
Spin Pedestal M 	×15 or 20×15 or 20×15 or 20×8 or 10/5 or 7×5 or 7/8 or 10 	Monday, Wednesday, Sunday
Spin Pedestal L 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Monday, Wednesday, Sunday
Spin Pedestal XL 	×40 or 50×40 or 50×40 or 50×20 or 25/13 or 16×13 or 16/20 or 25	Monday, Wednesday, Friday, Sunday
Spinback Pedestal M 	×15 or 20×15 or 20×15 or 20×8 or 10/5 or 7×5 or 7/8 or 10 	Tuesday, Thursday, Sunday
Spinback Pedestal L 	×20 or 25×20 or 25×20 or 25×10 or 12/7 or 9×7 or 9/10 or 12 	Tuesday, Thursday, Sunday
Spinback Pedestal XL	×40 or 50×40 or 50×40 or 50×20 or 25/13 or 16×13 or 16/20 or 25	Tuesday, Thursday, Saturday, Sunday
Night Pedestal L 	×20 or 25/13 or 16×13 or 16/20 or 25 	Tuesday, Sunday
Night Pedestal XL 	×25 or 30/16 or 20×16 or 20/25 or 30 	Thursday, Sunday
Dawn Pedestal L 	×20 or 25/13 or 16×13 or 16/20 or 25 	Monday, Sunday
Dawn Pedestal XL 	×25 or 30/16 or 20×16 or 20/25 or 30 	Wednesday, Sunday
Diamond Pedestal L 	×25 or 30/16 or 20×16 or 20/25 or 30 	Monday, Friday, Sunday
Diamond Pedestal XL 	×30 or 35/20-23×20-23/30 or 35 	Wednesday, Saturday, Sunday
Pearl Pedestal L 	×25 or 30/16 or 20×16 or 20/25 or 30 	Tuesday, Friday, Sunday
Pearl Pedestal XL 	×30 or 35/20-23×20-23/30 or 35 	Thursday, Saturday, Sunday
TM02 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM05 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM19 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM26 	×13 or 15×13 or 15×13 or 15×10 or 12/8 or 10×8 or 10/10 or 12 	Random selection of TMs each day
TM30 	×10 or 12×10 or 12×10 or 12×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM31 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM36 	×10 or 12×10 or 12×10 or 12×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM39 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM40 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM42 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM43 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM50 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM51 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM53 	×10 or 12×10 or 12×10 or 12×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM59 	×10 or 12×10 or 12×10 or 12×8 or 10/5 or 8×5 or 8/8 or 10 	Random selection of TMs each day
TM64 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM71 	×13 or 15×13 or 15×13 or 15×10 or 12/8 or 10×8 or 10/10 or 12 	Random selection of TMs each day
TM78 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM79 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM80 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM84 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM95 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
TM99 	×8 or 10×8 or 10×8 or 10×5 or 8/3 or 5×3 or 5/5 or 8 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
 	 	Random selection of TMs each day
===Secret base expansion===
Number of spheres required	Expansion
×60×60×60×30×30 	Increases size of Secret Base to 14×8 tiles
×40×40×40×20×20 	Increases size of Secret Base to 14×10 tiles
==Artwork==
Key artwork of and in the Grand Underground from
==Trivia==
* Despite the change in its layout, the Grand Underground maintains , similar to the Underground.
==In other languages==
Pokémon Hideaway
==Related articles==
Category:Sinnoh locations
Category:Brilliant Diamond and Shining Pearl locations
Category:Caves
es:Grutas del Subsuelo
fr:Grands Souterrains
it:Grandi Sotterranei
ja:ちかだいどうくつ
zh:地下大洞窟