These wire animal sculptures commemorate the exotic inhabitants that once called the Tower of London home.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

An architectural oddity hides in plain sight on this iconic London bridge.

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

The world's longest known cave system.

One of the largest collections of merchandise from the famous British sci-fi show can be found smack in the middle of Indiana.

For over 100 years, this Indiana town has had a tree growing out the top of the local courthouse.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

The unbelievably opulent home built for an infamous newspaperman.

The world’s largest concentrated solar plant generates as many problems as megawatts.

A chain of bells connect the California Missions and honor the legend of the "King’s Highway."

Mysterious meeting place for UFO hunters near Area 51.

The wild west is still alive and well at this authentic mining town watering hole.

This tea house was a hand-built gift from Boulder's sister city in Tajikstan.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

Down the road from where the Wright brothers lifted off is another flight tribute practically hidden from sight in the woods.

Once one of the world's great cities, Cahokia was a place of religious worship, trade and mass human sacrifice before being mysteriously abandoned.

This stunning concert hall has become a symbol of Iceland's national recovery.

An encyclopedic collection of mammal penises.

Scattered throughout London are ancient remnants of the city's former bounding wall.

Eighty million natural history specimens call this gargantuan museum home.

This now-abandoned outcrop is an important Native American spiritual site, overtaken by European settlers and mining pollution.

An eatery for UFO seekers on the Extraterrestrial Highway.