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

The world's tallest circular building is loaded with symbolism, but many just see a big donut.

Air-raid tunnels hidden beneath this opulent hotel provided shelter and an escape route—and one of the world's longest slides.

An imperial art museum offers edible versions of its most treasured displays in an on-site fine-dining restaurant.

Concrete balls on wires constructed to stop train surfing in Indonesia.

Established hundreds of years ago, Gandan remains the premier Buddhist monastery in Ulaanbaatar.

Old Muslim cemetery and resting place of folkloric creatures

Even though some of the buildings date back to the Victorian era, this research institute is still involved in cutting-edge astronomy research.

A memorial for public executions that dates back to the 14th century.

The birthplace of the Japanese idiom "wet clothes" meaning “false accusation."

A significant example of Czech cubist architecture—a style you won't find anywhere else in the world.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

This tree has witnessed nearly 1,000 years of history.

This ancient Corinthian helmet is South Korea’s only national treasure of Western origin.

A retro Yugoslav congress, cultural, and business hall built in the 1970s, with an iconic world clock.

The site of a Japanese traders’ settlement that once thrived in Ayutthaya, if for less than a century.

Soviet General Zhukov’s former home is a quiet spot amid the heavy traffic of Ulaanbaatar.

This unassuming bookstore in the heart of Madrid is one of the oldest in Spain.

Dedicated to the Father of the British Fire Service.

Hungarian Jews were ghettoized during the Second World War, but little remains of the original wall that closed the Jewish people off from the rest of the city.

This 23-foot-tall bear stands amid the hustle and bustle of Hamad International Airport.

Local folklore claims that this wall was not built for defense, but to provide labor during a time of famine.

The original span of a high bridge across the deep Crooked River Gorge has been preserved for pedestrian use.

Considered an architectural abomination by some, this metal-clad building is known as 'little red riding hood' by locals.