This medieval Estonian tower provides access to a series of tunnels that have been home to soldiers, punks, and fine art.

Disused seaplane hangar gets a second life as the jaw-dropping home of Estonia's museum of maritime history.

An empty relic of the Moscow Olympics crumbles away in Estonia's capital.

Also known as the Square Colosseum, this building is a prime example of fascist-era rationalist architecture.

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

This demon atop the Notre-Dame de Paris looks utterly bored.

The celebrated eyesore created by starry-eyed sweethearts.

This 18th-century sundial was designed to calculate the date of Easter each year.

This bridge was constructed from the rubble of the infamous Bastille.

This former “ante-chamber to the guillotine” has been refurbished to illustrate the brutal history of French justice.

An early 20th-century bullring converted into a modern shopping center.

This colorful statue welcomes visitors to a Barcelona park.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

One of the few surviving "Wigwam"-themed motels.

The pan man stands as a testament to the functionality of American cast iron cookware.

This ghost town houses the remains of Alabama's old state capital.

This small hut in the middle of a parking lot was once the wooded sanctuary of the 'Hermit of Montrose.'

This popular park is home to a sea serpent sculpture that now overshadows the twisted history of its creation.

This church houses the “incorrupt” body of its founding Bishop.

A spiritual vortex among the red rocks in Sedona.

A Florida college boasts the world's largest single-site collection of structures designed by Frank Lloyd Wright.

One of Frank Lloyd Wright's final works was this UFO church.