A striking symbol of the Bulgarian capital.

The temple that withstood the Nazis.

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

This massive stone and steel monument remembers a century-old battle that cost thousands of lives and nearly destroyed the city.

This once-grandiose behemoth of a monument from the socialist era now sits quiet and closed up.

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

This massive concrete sculpture is said to be the heaviest communist monument on Earth.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

An abandoned saucer-shaped monument in the Bulgarian mountains.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

The signs of a long buried road can still be found hidden beneath a London sewer grate.

When this test site was abandoned, they didn't even bother to take the rocket with them.

A mysterious castle built as a monument to lost love.

The final resting place of Christopher Columbus - or possibly someone else.

The first official clock in North America, it kept time for the Spanish government of Santo Domingo.

Built in 1512, the oldest cathedral in the Americas.

One of the first sewers in the Americas.

Learn the history of Dominican rum production.

The first hospital in the New World.

A macabre sculpture museum in the capital of Haiti fuses human bones with broken metal to create challenging contemporary art.

A nuclear power plant abandoned along with an international allegience.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

A local landmark that has become a hub of graffiti and urban exploration.