This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

A triumphant marble and bronze fountain depicting a 15th-century Hungarian king and his hunting party.

From cartoon characters to tiny tanks, a guerilla sculptor's little bronze statues are hidden throughout the city of Budapest.

The true meaning behind this sculpture remains unknown.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A museum in the childhood house of a medical pioneer.

Tucked away near more famous landmarks lies a statue meant to symbolize the confluence and continuing development of human culture.

Once the home of a hermetic monk, this cave now houses a small church.

The geographical center of Budapest is marked with a 10-foot-tall stylized zero.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

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

This statue of a falling man commemorates a teenage martyr of the Hungarian Revolution.

An unusual stone chair can be found on the banks of the River Wear, not far from Durham Cathedral.

The ruins of a once-grand castle that played host to a tournament with 100,000 attendees.

Now in ruins, this abbey was the home of Tironensian monks for more than 400 years.

The ruins of a small church belonging to a powerful Scottish family still hold the remains of its patriarch.

A square stone tomb marks the spot where six men were killed while holding a service in Caldoris Wood.

On a hill overlooking Loch Trool, a granite boulder marks the site where Robert the Bruce, King of Scotland, defeated an English army.

Now in ruins, this castle stood for centuries and saw a number of gruesome events.

The grave of a man who spent 23 days trapped underground after a mine collapse.

A circle made up of 19 boulders has stood in Scotland's Bladnoch Valley for some 4,000 years.

This fortified L-shaped tower is the ancient seat of clan Hannay.

A 2,000-year-old Iron Age fort offers stunning ocean views.

These stones date back to the 3rd or 2nd millennium B.C.