One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

This one-time health resort was used by aristocrats around the world.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

A miniature train-ride through Slovenia's largest cave system.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

This prison on the Maltese island of Gozo is almost 500 years old, and they have the graffiti to prove it.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

These temples are among the oldest free-standing stone buildings in the world.

Increasingly decayed figures stand as a powerful reminder of the human costs of Czech Communism.

The somber sculptures commemorating Irish Famine on the river Liffey in Dublin.

A diminutive, thousand-year-old church believed to be the smallest in Ireland.

Mortarless walls that stretch for miles are a lovely solution for creating grazing land in the harsh terrain of the Aran Islands.

These mechanical goats first battled it out in the year 1551, all because of an overcooked deer.

The traditional Polish croissant, folded 81 times into the shape of a horseshoe, is a legally protected cultural treat.

The mysterious empty cupola behind the monumental arch points to an ancient prophecy of Delhi.

An imperial fortress city that incorporated cultural elements from the entire Mughal empire, only to be abandoned the year it was finished.

This abandoned stepwell is one of the largest, deepest, and certainly one of the creepiest in India.

This opulent 16th-century Maharaja’s palace is a unique mix of Hindu and Muslim designs.

More than half of this Indian palace is drowned but it looks all the more spectacular for it.

The world's second-largest sundial, made entirely out of stone.

The 953 windows undoubtedly make this the world's most beautiful screened porch.

This massive subterranean fissure is known as the "underground Grand Canyon."

A crumbling World War I fort that is reached through a series of concrete tunnels.

The monument honors the mountaineers who were part of Europe’s best anti-Nazi forces.