Britain’s longest ancient monument, this great 8th century earthwork was built to mark the boundary between what would become England and Wales.

A quirky assortment of musical marvels from around the world.

A long spiraling walkway winds through the woods, and around a copper beech tree at the center.

A 17th-century church is nestled within the walls of a 15th-century ruin.

The Virginia home of one of the signers of the Declaration of Independence is being preserved with a unique glass facade.

Home of the unusual art of water puppetry, one of Vietnam's oldest curiosities.

These chunky stone towers out in Lake Michigan are the key to Chicago’s drinking water.

Mysterious ancient petroglyphs carved on a glacial boulder at the tip of Bainbridge Island.

Home to a full cast of the largest woolly mammoth ever recovered in North America. 

Perhaps the only prehistoric monument with its very own public bus stop.

These seven moai figures are the world's only sanctioned replicas of the Easter Island originals.

The only way to visit this old resort hotel is with scuba gear.

The oldest still-inhabited hill fort in India looks like a magnificent golden sandcastle.

Stockholm's tiniest statue is of a small boy looking at the Moon.

A little-visited waterfall in an otherworldly landscape.

A UFO scrapyard in the California desert.

Public access to clean drinking water was an instant hit among the masses.

Built in the 1300s, this magnificent building that hosted England's kings and queens transports you to the Middle Ages.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

This bridge was constructed from the rubble of the infamous Bastille.

The Argonaute submarine was the French navy's pride and joy in the 1950's.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

135 bronze medallions mark a French meridian line which once rivaled the hotshot Greenwich timeline.

Saintly bones pressed into a wax effigy of a Catholic superstar.