Tower with a double-helix spiral, adorned with letters of the Georgian alphabet.

A literally moving statue of stacked metal giants just continually trying (and failing) to find love.

A Turkish monastery tucked into a cliff wall.

Carefully reconstructed after the Bosnian War, this 16th-century bridge stands as a symbol of the country's enduring multicultural heritage.

Bridge that died in war and was resurected.

This crucial gathering spot along the "hippie trail" still displays old notes between traveling beatniks and backpackers.

Ancient serpentine sacrifice holder that has stood the test of time.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

A fountain standing as a testament to a doomed alliance.

One of the newest mosques in a city filled with thousands.

Climb a steep hill in 90 seconds on the second-oldest urban subway in the world.

The legendary luxury train passage is commemorated with a charming museum inside its former eastern terminus.

A marvel of Byzantine engineering under the streets of Istanbul.

Taking the subway here means doing so over a bridge located in the middle of an estuary.

This castle has links to Portugal’s founding and struggles for independence.

This restored Portuguese cafe may well be the most beautiful place in the world to grab a Big Mac.

Elaborate tile work in this railway station tells the story of Portugal.

The stunning interior of this Gothic church is covered in ornate gold details.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

A replica of the Roman emperor in glorious full color.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

This one-time health resort was used by aristocrats around the world.

The Adriatic's most famous wind can be reliably experienced in the city's Marina.

A beautiful ruin of a 14th-century Plantagenet castle built by a medieval mercenary.