About this episode
Throughout history, humankind has turned its gaze towards the heavens in search of mystery. Yet time and again, it is beneath the ground where the most enduring enigmas are found. Across every continent lie tales of ancient tunnels, lost chambers, and sealed structures that predate all known civilisation. One such story emerged from the mountains of wartime Slovakia, where a wounded soldier claimed to have uncovered something buried deep within the earth, its surface smooth as glass, hard as diamond, and impossible to explain. MUSIC Tracks used by kind permission of Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 3.0 Tracks used by kind permission of CO.AG Learn more about your ad choices. Visit megaphone.fm/adchoices