User aaaaaatttuyy has not mentioned the fact that NASA has recently found a crater under the Hiawatha glacier in Greenland that was, at the time of discovery, supposed to be 12k to 3M years old.

But a paper from March that tries to cross-validate this finding by looking at sedimentary data in South-America finds that the impact must have occurred 12,835 ~ 12,735 years ago.

Source: https://www.nature.com/articles/s41598-018-38089-y#ref-CR25

And this, is what Graham Hancock has been supporting for so long. And yeah Semmelweis was full of himself as well.

Now to answer your questions about archeological sites:

- Atlantis (when) https://www.youtube.com/watch?v=tSx_0stJI0w
- Atlantis (where, the Richat Structure) https://www.youtube.com/watch?v=oDoM4BmoDQM&t=230s
- Göbekli Tepe https://www.youtube.com/watch?v=6K5NvCiYGEI
- Underground city around the world: https://www.youtube.com/watch?v=zMjbtb4xLGQ&t=5s
- Underground city under the Giza plateau https://www.youtube.com/watch?v=BVR5V-cmpbA
- Huge cities in the Amazon bassin (a giant garden) https://www.youtube.com/watch?v=Cn1MugPalaA&t=608s
- The Sphynx of Egypt is more ancient than thought https://www.youtube.com/watch?v=N9aZlLqkcYw
- Underwater city in japan https://www.youtube.com/watch?v=-vHbpimRQLg&t=47s
- Underwater city off the coast of Cuba https://www.youtube.com/watch?v=JhcCjbl2Vjc
- Similarity between various archeological sites: https://www.youtube.com/watch?v=eYfpu2sHZuo
- The Antikythera Mechanism https://www.youtube.com/watch?v=hkL5Wkj1gYk
- The Ellora caves in India (as much work as the buildingof the great pyramid): https://www.youtube.com/watch?v=_WypT8RPUxg
- The "laser-cut" Lomas Rishi caves (India again): https://www.youtube.com/watch?v=ShObd9t_0Oc
- The fact the Giza pyramid and some megalithic structures around the world (some in Corsica for instance) are north-aligned with a greater precision than Copernic's observatory: https://www.youtube.com/watch?v=NDBA3fhCfmo
- The Sahara used to be green and turned into sand in a generation, around **11,000** years ago: https://www.smithsonianmag.com/science-nature/what-really-turned-sahara-desert-green-oasis-wasteland-180962668/
- The Great Pyramid could be a giant ram pump : https://www.youtube.com/watch?v=QDUwD59OYzI&t=122s
- The pyramids could be made of artificial re-agglomerated limestone : https://www.youtube.com/watch?v=znQk_yBHre4
- The Machu Pichu has not been built by the Incas and the walls were made out of molten stone.
- Organic matter in the incredible ruins of Puma Punku, Peru, show stones where made by pouring a geopolymer into casts: https://www.youtube.com/watch?v=0Q1f0YBm4ic&t=317s
- Etc ...

The list is long, and as you may have noticed, I tried to pick
short videos here. Also most of them are "crackpot" theories from youtube. It may be unbearable to watch if you like to razzor-cut bushes the Occam style. Now if you like to watch them grow into a passionately intricated puzzle and can enjoy these videos like a Netflix series, this might interest you.

A few channels/authors to follow on the matter:

- Graham Hancock
- Ancient Architects: https://www.youtube.com/channel/UCscI4NOggNSN-Si5QgErNCw. Both crackpot theories and scientific news related to the topic. Very prolific
- Bright Insight: https://www.youtube.com/channel/UCsIlJ9eYylZQcyfMOPNUz9w/videos. Similar, but more crackpot.
- Le Moment Curieux (french) : https://www.youtube.com/channel/UCyVPaIiBL9ieiyMeoCTR0SQ. Deep analysis of cyclopean/polygonal walls around the world + a toy-model of the Great Pyramid as a pump.
- Suspicious0bservers's Earth Catostrophe Cycle: https://www.youtube.com/watch?v=wvjJqIXYT1w&list=PLHSoxioQtwZfY2ISsNBzJ-aOZ3APVS8br most stars including the sun cyclically burst into "micro-nova" events and cause poles to shift. This is Roland Emmerich grade entertainment and very enjoyable. Very scientific as well altough a tad conspirationist.
- The science behind comet capture then disintegration in the solar system: https://cosmictusk.com/how_a_disintegrated_comet_destroyed_the_world/

But the best way to deep into the subject (warning, lot of numerology ahead!) is this documentary and its sequel:

- The Revelation of the Pyramids: https://www.youtube.com/watch?v=2fS9ixfQ_no&t=793s
- Builders of the Ancient World: https://www.youtube.com/watch?v=okhDDknJ9o0&list=PLt3D1556v66JLCCEtdI7spskIsvDUwylw&index=1

Good luck