Derweze is a place in Turkmenistan where there is a really big hole in the ground that keeps burning. A long time ago, some people were looking for oil there and they accidentally made this big hole because the ground collapsed and they were afraid they would release poisonous gases, so they decided to set the hole on fire to burn the gases away.
But the fire didn't stop burning, and it's been burning for over 40 years now. It's like a really big bonfire that never goes out, and the flames can get really high. Some people call it the "Door to Hell" because it looks like a big hole leading to hell.
Even though it's very hot and dangerous around the hole, scientists and curious people still visit it to study the flames and learn more about how it works.