Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

The Vatican's secret porn-festooned bathroom was painted in erotic murals by one of the greatest artists of the Renaissance.

Breathtaking and huge 430 year old maps of Italy.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

These millipedes glow not out of attraction, but as a not-too-subtle warning.

This mountain tram provides stunning views while hanging from a single, steel thread.

This historic black and white monastery is one of Bulgaria's architectural jewels.

300-year-old villagers houses and traditional churches preserve a nearly lost piece of Russian history.

This 15th-century island fortress later served as home to the executioners no one wanted to live near.

This beautiful ancient site is dotted with perforated sandstone pillars considered sacred by some Native American groups.

While these wooden totems bear a striking resemblance to First Nations artwork of British Columbia, their actual origins lay on the opposite side of the Pacific Ocean.

Two giant painted cooling towers make for one of the world’s most epic bungee jumps.

This famous Nevada gold mine, once a hotbed of Wild West shenanigans, is now open for tours.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

A five-square-mile slice of Spain on the Mediterranean coast of North Africa.

This rare volcano spews the strangest and (literally) coolest lava in the world.

Burping, gurgling geothermal mud pots by the Salton Sea.

This stunning natural double arch, the largest in the Alps, went undiscovered until 2005.

This otherworldly palace-mausoleum complex is the stuff eternal dreams are made of.

These stairs were built to accommodate royals mounted on elephants.