The true age of this ancient stone circle is unknown, but its stunning vista isn't in question.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

Remnants of the 16th-century defensive wall still stand unassumingly within Edinburgh.

The most loyal of little dogs, or a Victorian era publicity stunt?

Protecting the dead from opportunistic body snatchers.

This 17th-century street hidden beneath Edinburgh was once a breeding ground for the black death.

360° views of the city plus five floors of optical illusions and hands-on science.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

This demon atop the Notre-Dame de Paris looks utterly bored.

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

This statue was given to France by the United States to commemorate the centennial of the French Revolution.

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

The remains of this castle, known as the Witch’s Eye, watch over the Thur Valley.

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

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Walk in the footsteps of the gods and straddle two tectonic plates.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

Medicinal spa created from the mineral-rich runoff of a geothermal power plant

A remarkably intact castle that once was the largest in Ireland.

The oldest pub in Ireland may also be the oldest surviving bar in the entire world.

The ancient tomb acts as a calendar that keeps perfect time.

This was the second largest mercury mine in the world and one of the oldest preserved mine complexes in Europe.