Summer in Scotland begins with a spectacularly wild and colorful event rooted in ancient pagan traditions.

The fountain marks the area where hundreds of accused witches were burned at the stake.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

The U.K.'s first underground railway line is now a lively thoroughfare for runners and cyclists.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

This small museum in a 17th-century building honors three iconic Scottish writers.

A sweet symbol marks the place where torturous executions were once carried out.

A labyrinthine network of chambers with a storied past hides below Edinburgh's South Bridge.

The Scottish Reformation leader's grave was paved over and is now a parking lot.

Accessible only at low tide, the deserted island is dotted with World War II ruins.

These ancient sea caves hold Britain's highest concentration of Pictish rock carvings.

A trio of giant megalithic stones in the middle of a golf course.

This Scottish castle has witnessed clan rivalries, Jacobite uprisings, whisky smuggling, and more.

A glacial pothole was once a hideout for a notorious Scottish outlaw.

A short distance from the Eiffel Tower is the final resting place of several of the city’s more well-known and interesting characters.

Museum on French naval history, with magnificent figureheads, a historic diving suit, and a boat used by Napoleon.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

The first green space constructed on an elevated viaduct.

France's most famous cemetery, with some of its most curious tombs.

This structure atop a craggy cliff in one of the most beautiful parks in Paris boasts an unbeatable view.

A unrivaled and rather horrifying collection of wax dermatological models.

France's national museum of scientific and industrial instruments.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.