A nightmare for the claustrophobic lies hidden in Southeast Asia.

Malaysian fireflies create a dazzling display as thousands light up in unison.

Next to the Malaysian Prime Minister’s office stands this rose-colored mosque.

Holy Hindu shrine in an enormous, monkey-filled limestone cavern.

The remains of what was the most important religious complex in coastal Peru for over a millennium.

Preserved Inca city and site of the last Inca stronghold against the Spanish conquistadors.

Did Inca children also slide down these smooth rocky slopes above Cusco?

The stones of this Incan wall complex fit together so well you couldn't fit a piece of paper between some of them.

Built on the remains of one the Incas’ most important gathering spots, this square keeps the spirit of a fallen empire alive.

Situated on a sacred Inca site, this 16th-century cathedral took nearly 100 years to build.

This geometric feat is a testament to the Incas' mesmerizing architectural abilities.

The retired vessel is South America's first floating museum.

Haunted by its violent past, this colonial bastion was the largest Spanish military installation in the Americas.

A small, emotionally charged room inside the Mario Testino Museum dedicated to Princess Diana and one famous photo shoot.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

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

An underground city of salt.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

Macabre astrological automaton clock dating to the late 1400s.

A plaque marks the spot where the saint was shoved off the Charles Bridge and into the river.

A mocking tribute to the past and modern leadership of Prague.

This doorless 20th-century elevator doesn't stop or slow down.

This automated sculpture of two men peeing will spell out text messages with their micturition.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.