These photos were taken deep underground within the miles of abandoned mines beneath Yekaterinburg, Russia . Layers of carnallite -- a mineral used in fertilizers -- band the tunnel walls, producing these technicolor masterpieces. Think a subterranean version of China's stunning rainbow mountains .

A small portion of the carnallite mines remain in use, but most of the passageways are now closed and off-limits to the public without a special government permit, according to photographer Mikhail Mishainik. Take a look at a few more photos of the caves below.