A futuristic, brutalist masterpiece that is also strangely prison-like.

An underground city of salt.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

The 953 windows undoubtedly make this the world's most beautiful screened porch.

Romania's triumphal arch looks out over Bucharest.

The oldest housing complex in Riga is a mini timeline of architectural trends.

Copenhagen's celebrated theme park and gardens.

The world's longest outdoor covered escalator system transports commuters through Hong Kong's hilly terrain.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

Elevated freight railway turned wildly successful urban park.

The design of the Palacio Salvo has been described as "a lighthouse on top of a building."

The once highest point in China blends symbolic design with a kick of adrenaline.

A natural arch offers panoramic views of Yangshuo's karst hills.

Built in 1512, the oldest cathedral in the Americas.

After Christopher Columbus died, his son built a fancy house to rule from.

The first hospital in the New World.

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

Home to 23 voluptuous and instantly lovable sculptures by one of Latin America's most celebrated artists.

This Bogotá museum houses the world's largest collection of pre-Columbian gold relics.

An unusual and beautiful form of mass transit serves the city's steepest neighborhoods.

A 10 million-ton rock once worshiped by the Tahamies Indians, accessed by an astounding staircase.

The Andean town where every single building is decorated with a brightly colored frieze.

Museum precariously perched on a massive yellow pillar.

Solitary monument dedicated to the beauty of nature.