A perfect circle of 24 mysterious holes dates back to prehistoric times.

Teeming with illegal goods and services, this towering maze of vice is also a popular tourist accommodation.

A biblically accurate ark located beneath a Hong Kong bridge is fun for the whole Christian family.

What looks like a crashed Zeppelin is actually a bright, airy reading room perched atop a modern museum.

The oldest garden in Prague, once part of an medieval orchard.

A crucified and bearded female saint.

Monument to a suicide protesting the Soviet invasion.

Microscopic scenes; some call it novelty, some call it art.

The risqué mixed-media sculptures are supposedly a metaphor for Czech politics.

Twelve grave-faced marble angels guard the emperor's tomb at Les Invalides.

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

This life-size replica of the Statue of Liberty's flame is also a tribute to Princess Diana by default.

This crumbling, graffiti-covered mansion sits tantalizingly within reach of the proletariat who frequent a public park.

Remnants of the most densely packed city in world history, that thrived on anarchy for 30 years.

A colossal floating restaurant built to look like a ancient Chinese imperial palace.

This hulking behemoth is actually five interconnected towers built in the 1960s.

Secret gardens just a few miles from downtown Atlanta.

This massive store is home to an eccentric collection of vintage, retro, and peculiar goods.

The world's largest statue of Mao Zedong looks out over the city where he discovered Communism.

A lone cannonball remains lodged in the walls of the Hotel de Sens as a sober reminder of a revolution.

China's very own Atlantis is an ornate dynastic city resting at the bottom of a lake.

Mirrored floors and arched shelves create the illusion of an infinite tunnel of books.

This abandoned fishing settlement may well be the greenest village in the world.

China's most famous acrobatics act.