A forgotten remnant of the Soviet Union, Transnistria is an unrecognized country hidden behind a heavily militarized border between Moldova and Ukraine.

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

A discreet little stairway on St. Nicholas Avenue leads to a quaint and unexpected cobblestone street of 19th century wooden rowhouses.

The longest continuous underwater road in North America was built at the insistence of Franklin Roosevelt.

A historic 1890s architectural masterpiece with an iconic clock tower that, once open to the public, now faces an uncertain future.

A Manhattan office building is home to the world's largest chess board.

Designed by Buckminster Fuller, this relic of the 67 Expo survived fire and ice.

A fiery crater has been burning in the Karakum Desert since 1971.

Site of the first pathological and bacteriological research facility in the United States.

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

Come for the flowers, stay for the bats!

This historic observatory contains the world's oldest refracting lens telescope.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

Russian history in San Francisco.

Early prototype for Frank Lloyd Wright's Guggenheim.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

An extraordinary museum devoted to the pop art legend created by Slovak artists.

Twisted buildings adorn the banks of the Rhine river.

3,000 market stands in five former Zeppelin hangars.

A black cat protests the City Guild in Riga's Old Town.

340-foot statue built to honour the Heroes of the Soviet Union.

Museum celebrating the achievements of the Soviet space program.

Moscow's most popular cemetery includes the graves of numerous cosmonauts.