Hidden beneath the streets of London is a secret subway that only carried mail.

Sitting in the basement of a castle, the largest wine barrel in the world is bigger than most apartments.

The shockingly unspoiled Peruvian tomb of the Lord of Sipan was once guarded by a footless warrior.

Discovered after draining a local pond, these ancient man-made caves are still a complete mystery.

This submersible road connecting a French island to the mainland is lined with safety towers for when the tide strands travelers.

The city of Rockford, Illinois is symbolically protected by a quartet of fittingly stony sentinels.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

Hidden in a secluded Greek cove is a pristine beach marred only by the rusting smuggler's hulk stranded on its shores.

These Stalin-era industrial 'death traps' hang lifeless above the city

The largest university building in the West is a gothic masterpiece containing dozens of theme rooms based on different countries.

A take-out restaurant that only serves cuisine from countries with which the United States is in conflict.

A restored Pittsburgh house of God has been converted to a marvelous house of suds.

Mirrors and glass shards cover every inch of this arrestingly beautiful mosque.

Museum design and public transportation meet in this unique Russian train car.

A very classy 1920s-era bar right in Grand Central Station.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

This museum celebrating the almighty dollar lets visitors literally stand in the shadow of a million bucks.

Medical history museum featuring a lovely doctor's office from the 1800s.

The angel of death appears to weep black tears at this grave marker.

A collection of unique outdoor sculptures surounded by the beauty of nature.

Museum dedicated to the struggles of the disabled.

A natural gas leak provides a flickering flame beneath a waterfall.

Extravagant mosque honors modern Islam.

Unique antiquarian shop specializing in globes, maps, and prints.