This 14th century castle withstood years of battle but is now sliding off the hills into the Danube.

A towering spire in the fortress of Kalemegdan honors the victorious armies of Serbia during their struggles against the Ottoman Empire.

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

Historic beer hall in Bucharest with magnificent stained glass and a lively folk band.

The preserved arm of a third-century sorcerer is believed to have the power to lift curses and spells.

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

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

A battleship’s mast sits atop a turret-like memorial, commemorating those who lost their lives in one of the precipitating events of the Spanish-American War.

This 11th-century Cistercian abbey was once seized by Henry VIII.

Legend says that Wade the Giant scooped up a handful of earth to throw at his wife, leaving behind this round valley.

These planks were originally installed to hold the dead.

These 20-foot jaw bones honor a time when the leviathan bones were a sign that whalers survived the hunt.

These carved, weathered stones once gave mail carriers and pub goers a leg up.

The curious and tiny collection contains some very odd objects.

The ritual has been performed uninterrupted for nearly 700 years.

Richard III supposedly disposed of his nephews' bodies here in an effort to seal his claim to the throne.

Graffiti from the 16th and 17th centuries cover the walls of this part of the Tower of London.

The watery entrance for condemned prisoners heading to the Tower of London is still visible along the Thames.

The final resting place of the great navigator, or maybe his brother.

The world's largest wooden structure.

Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

There has been an astronomical clock on this spot since the 14th century.

A copy of the Statue of Liberty greets visitors to the birthplace of Auguste Bartholdi.

Every half hour the eye-rolling clock face sticks out its tongue to mock the good citizens of Koblenz.