Gustave Eiffel's masterpiece until the Eiffel Tower was built.

Nine limestone rock stacks on Australia's "Shipwreck Coast."

Prehistoric park filled with the fossils of dozens of extinct species including Australian megafauna.

Aqua white sand highlighted with fiery red rocks.

Alien rock formations grown from the sands of an Australian national park.

These Australian rock formations look like Martian beehives that have grown up out of the landscape.

Legend says entire herds of cattle have disappeared within this boulder-strewn landscape.

This ancient limestone cave system contains many impressive geological features.

One of the breathing caves of Australia's Nullarbor Plain.

An impressive site containing some of the earth’s rarest living fossils.

A poignant monument dedicated to a tragic 1930s plane crash.

A haunting museum chronicling the bloodiest battlefield of World War I.

A 16th-century Andalusian palace.

Hidden behind a wall, Spanish nuns distribute their signature sweets on a revolving tray.

The world's largest wooden structure.

The 5,000-year-old megalith is believed to be Scotland's tallest standing stone.

A ruined Maya city that suffered a years-long case of mistaken identity.

A measuring mishap led to these artificial stone ladies losing their stomachs.

Deep in the countryside lie the remains of one of the grandest Roman dwellings in Britain.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

This 30-foot pile of rocks may be the grave of a mythological Irish queen.

A tiny microvalley etched into the side of Knocknarea Mountain hides another world.