Raging Subterrain

Рагинг Субтерране, which translates to "Raging Subterrane" in English, is a cave found in Drvengrad, Serbia which was originally intended to be a coal mine but got repurposed to a mass grave for victims of World War 2.
This cave/mass grave was home to the most dangerous interdimensional demon, YoY.
==History==
===Madenciler ve çapalar===
A now defunct Ottoman mining company named "Madenciler ve çapalar" discovered one day in the late 1810s this cave which was rich in coal. So they decided to exploit this discovery by using many ore extracting machines they made. With time, they figured out that the deeper they go underground the richer the resources become, so what harm would come if they continued digging straight down deeper and deeper? Well the entire world collapsing, that is. But besides that, at one point in 1719, they felt the scorching heat of what they thought was the Earth's core, and the pressure was so high they thought they were gonna implode internally. Another strange thing they experienced down there was that they heard a large roaring sound, which to them sounded like a large number of people screaming. They ignored this and continued to dig deeper until the machine cracks open a narrow hole at the bottom, everything got hotter, louder and more painful. They were never seen again. 
===YoY===
YoY, a hellish interdimensional being exiled from his homeland, discovered an opening in Hell's ceiling, so he decided to go through it. Today, YoY is the only confirmed demon to have used this crevice in order to enter our realm. 
==Present Day==
The Serbian Government decided to board off Рагинг Субтерране using robust metal barricade in 2014 so nothing can ever get in or out. This decision was made due to the fact that this mass grave was the origin of many missing children's cases, a hotspot for disposing of murder evidence, and even urban legends and mythos that aren't just YoY's and it is rumored to be cursed. Now it is repurposed to be a tourist site (from the outside ofc) because of how historic it is.
==Trivia==
*Howard Weedman was originally gonna find his parents in the catacombs of France but that got retconned
*The cave being a mass grave was based off of the idea of the paris catacombs
*The whole mining to Hell thing was inspired by the audio recorded by miners which conveyed the "screams of hell" or whatever i think its fake but idk
*The name of the mining company is a reference to one of the many Wheel of Fortune (a gameshow) fails where a dude says "miners and hoes" which was translated to turkish and thats the company's name