The oldest colonial fortress in the Americas was once the home and later prison of Christopher Columbus.

Built in 1512, the oldest cathedral in the Americas.

Every Sunday, Bogotá turns 75 miles of its city streets into a bicycle superhighway.

This tiny shop has been serving traditional tamales for more than 200 years.

Towering high above the neighborhood of La Candelaria, the church is easily recognizable by its distinctive red-and-white striped facade.

Pilgrims each carried a brick to the top of Mount Monserrate to help build this historic sanctuary in Colombia.

The second-largest giant sequoia in the world.

Quite simply the largest tree in the world (by volume).

A 19th-century cabin built into a hollowed-out Sequoia tree.

Four hundred granite steps were built into this massive rock by the National Park Service.

This small shack near the entrance to Sequoia National Park has been in almost continuous operation for the last century.

This German bone house contains the remains of some 20,000 souls.

A memorial for a young woman and her ghost, which are claimed to have caused countless deathly shipwrecks.

Tiny castle in the middle of the Rhine made you pay to pass.

Fantastic views and thousands of love locks.

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

Turkish adventurer antiques in the heart of the Grand Bazaar.

1513 Turkish world map, full of European state secrets and snarky commentary.

No one is sure if the world's fourth-largest diamond had been found in a rubbish heap or was pawned by Napoleon's mom.

A section of the long chain that blocked enemy ships from entering Constantinople.

Five sultans and their families rest in eternal splendor, teeming with overlooked beauty and drama.

A marvel of Byzantine engineering under the streets of Istanbul.

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

A fountain standing as a testament to a doomed alliance.