Giant topiary dog once played a role in a terrorist bomb plot.

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

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

Seaside ruins of a settlement that date back to the first century B.C.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

The world's most active stratovolcano is almost always erupting.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

Climb inside an iron crystal magnified 165 billion times its normal size.

A little sculpture with a large wardrobe.

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

Fountain where visitors can earn a license to be mad.

A 16th-century horror show built in a lovely Italian garden.

Water and windows define this defensive Italian well.

This 16th-century monastery has been turned into a surrealist architecture compound.

A volcanic old faithful, Stromboli has been erupting continuously for the last 2000 years.

Italian cave with exceptional acoustics and an unsavory history.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

Ancient mysterious ruts carved in the bedrock.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.