The remnants of an early American attempt at missile defense.

The watery grave of an impractical idea.

The largest radio telescope in the world searches for extraterrestrial life from the remote limestone peaks of southern China.

It's home to the antenna that received the first images of Neil Armstrong walking on the moon.

A long-abandoned provincial prison left to crumble in the frigid air of Ontario.

A school teacher's massive and terrifying self-built castle.

Stunning views over Ontario's old-growth pine forests.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

The abandoned remains of this Victorian brewery hide crumbling bowling alleys and rusting industrial gear.

The walls of Germany's Parliament still show the scars of the Red Army takeover in World War II.

Reminders of the Battle of Berlin still scar the railway.

The site of the famous Nazi book burning campaign of 1933 remembers its "Night of Shame".

These former Nazi anti-aircraft towers offer a singular view of the north of Berlin in the summer, and a sanctuary for bats in winter.

Buried five stories underground, this Soviet bunker is packed with gas masks and Cold War paraphernalia.

A Jenga-style cylindrical tower of books that appears to go on forever.

Be(w)ar(e) the moat around this historic Czech castle.

An abandoned logging settlement nestled in the woods near a popular ski town.

From mining complex to industrial exhibition, this museum once played a major part in the X-Files.

This remote research station sits amid the second-largest ice sheet on the planet.

This quirky piece of naval artillery has been deafening Canadians for over a century.

This exuberantly curated landscape is one of the largest sculpture gardens in Canada.

This crumbling industrial fortress has attracted daredevils, filmmakers, and historians.

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

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.