This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

This once-derelict building is now one of the most beautiful bookstores in the world.

A centuries-old forgotten underworld lies beneath Malta.

"Holy Wisdom" overlooks the city that became its namesake.

This fortress dates back to the 6th century and is also the site of a controversial abandoned restoration project.

See how paper is made the old-fashioned way.

An Albanian monument to the Communism that nearly crushed the country is now a crumbling wreck.

A futuristic, brutalist masterpiece that is also strangely prison-like.

Legend has it that Napoleon Bonaparte fell in love with this Gothic church.

A black cat protests the City Guild in Riga's Old Town.

This dizzying tower was built to better broadcast the 1980 Moscow Olympics.

A series of caves under Castle Hill that once held the prisoner Vlad Tepes, better known as Count Dracula.

Its frescoes depict the likeness of Marshal Tito, Karl Marx, and Friedrich Engels burning in hell.

This virtually windowless mass of smooth concrete is the only Catholic church in the city.

The haunting ruins of a military fortress turned astronomical observatory sit on a Sarajevo mountaintop.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

A diminutive statue that was inspired by the sculptor's own daughter.

A monument to the bloody fight against fascism in Slovakia during World War II.

The topiary maze at the Habsburg hunting lodge.

In one of the world's smallest countries, a royal's personal winery is open to the public.

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

A once-thriving hotel in the Swiss Alps couldn't compete with climate change.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

This statue of the great Argentinian car driver is located near a famous curve of the Monaco Grand Prix.