However, a recent discovery came without any explanation, and was dubbed by those who saw it as a 'portal to the underworld'.
A huge crater reportedly appeared in the ground, in Gukovo, right on the border between Russia and Ukraine.
The hole was formed unexpectedly, and was apparently so deep that no one could see the bottom. Videos of the strange phenomenon have been circulating on social media, but it's worth noting that it hasn't yet been verified so it's hard to know if it really is what everyone says it is.
Footage of the hole was accompanied by some unsurprisingly alarmed exclamations. The man filming can be heard saying, according to the Daily Star: "It's so ******* deep it's scary to look at. You can't see how deep it is…"
He goes on, "It just ******* came out of nowhere... I don't even know how... deep it is. It just... collapsed underground".
It's not hard to imagine how creepy it would be, after all, to walk out of your home one morning only to find a bottomless pit has opened up meters from your front door.
Currently, the dominant theory is that the hole might have been caused by an old mineshaft collapsing far below - but that's slightly muddied by the fact there reportedly aren't any mines there.
However, while official mines and tunnels would be recorded in the area, not every mining operation is official, with some people resorting to building 'black gold' tunnels to try to harvest coal themselves.
These operations are unsurprisingly very dangerous due to a relative lack of safety equipment, and the proximity of the huge crater to some residential blocks underlines how close some buildings came to collapsing into it.
Still, the crater seems to have been filled in very quickly, which only helped fuel conspiracy theories - and of course, there are some out there who think this mysterious collapse was down to alien activity.
Either way, local residents can hopefully now move on without having to worry about the ground under their feet opening up again, whether it's a hole down to a mineshaft or truly a 'portal to the underworld'.