Thomas Page , CNN Written by

Ever had a tube journey from hell? How about a tube journey into hell -- or out of it, depending on which way you're traveling. Stockholm's underground is a bastion of subterranean design, and Radhuset metro station provides the Dante's Inferno of commutes.

It's cavernous interior, deep rouge and magma-like, may not require Virgil to navigate, but there's definitely a satanic charm to the 1970s design.

It's one of many underground marvels to be found throughout the world. From a theme park in a Romanian mine to a cathedral 660 feet below Colombia, there's a host of incredible spots deep within terra firma waiting to be explored.

Click the gallery below and let CNN Style take you on a journey to five continents, by way of ancient cities and Cold War boltholes. We hope you're not scared of the dark.