Built by engineer Konstantin Zverev in the 1870s, Fort Zverev now lies in ruins, with machine gun mounts, bunkers, and water tubes slowly rusting away.

But the part of Fort Zverev that feels truly nightmarish lies in the basement area, where in the 1970s, a fire erupted. However this wasn’t just any fire.

In this basement they stored a Russian alternative to napalm, and when it caught fire it reached temperatures of over 2000С, so hot in fact, that it literally melted the brick above it. In doing so it created a sort of artificial cave of red brick stalactites dripping down from above.

Today the fort, and its cave of dripping brick stalactites are still there, slowly falling back into the Russian countryside.