An FDR-era tuberculosis sanatorium has stood abandoned in the suburbs of the U.S. capital for over 30 years.

Cathedral carved out of salt, located a mile below the Earth's surface.

The entire town looks like a slice of Spain that was carted across the ocean and plunked in the Andes.

This colonial town in Colombia sits around the largest stone paved square in South America.

A museum built around a bus-sized fossil on the side of the highway.

This Bogotá museum houses the world's largest collection of pre-Columbian gold relics.

Pilgrims each carried a brick to the top of Mount Monserrate to help build this historic sanctuary in Colombia.

A celebration of Colombia’s premier contemporary artist.

Erected in 1803, it is the first astronomical observatory that was built in the Americas.

Colombia's biggest botanical garden contains plants from all across the country.

A sharp sculpture made of thousands of pieces of jagged glass.

An ancient octagonal weather station named for the eight Greek gods of wind.

This historic structure has been used as a mosque, a barracks, a prison, a school, and a bakery.

These ancient ruins hide in plain sight next to a dessert shop.

The only surviving choragic monument is a trophy awarded in 334 BC for the winning dramatic chorus.

This building displays the scars of the “Dekemvriana,” a dark time in modern Greek history.

A man's head is enshrined beneath a statue near the first building constructed for the modern Olympic Games.

The home of Greece’s national poet sits crumbling in the middle of a popular tourist district.

The site where hundreds of Greeks were tortured by the Nazi secret police is now a cosmetics store.

America's first federal monument.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

This dig site outside D.C. is known for its exceptionally high density of baby dinosaur fossils and dinosaur eggs.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

An unusual sculpture, an interesting history, in a strange place, for a good cause.