We often wonder what ancient cities looked like, what buildings, walls, and colors did they feature. But rarely do we ask: ...

In 1963, a man knocked down a wall in his home in Derinkuyu, Turkey, only to find something incredible on the other side. The ...

Paradise is dubbed as “the world’s largest underground city” and is built right underneath a mountain in Colorado. Agent Collins first learns about Paradise after a meeting at the White ...