This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A 16th-century Andalusian palace.

The world's largest wooden structure.

In the best of all possible worlds, everyone will get a chance to see this statue in which Voltaire's heart is interred.

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

France's most famous cemetery, with some of its most curious tombs.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

A haunting collection of the vanished and disappearing natural world.

19th century pendulum and a clock restored by a rogue group of guerilla artists.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Twice a day a speeding train passes only inches from the homes of this residential neighborhood.

Meant to be a lavish presidential home, the palace became a symbol of the fall of South Vietnam.

The notorious "Hanoi Hilton" where Vietnamese colonial subjects and later American POWs, including John McCain, were imprisoned.

Thailand's distressed elephants find peace at this Chiang Mai sanctuary.

This French colonial post office is arguably the grandest in all of Southeast Asia.

Life-sized painted illusions let pedestrians blend in with the street art.

Come in, light some incense, and ignore the live snakes around you.

5,000 skulls in memorial to those killed by the Khmer Rouge.