Go inside to really appreciate this 500-year-old technological masterpiece.

This clock tower is all that remains of Bird Hall, constructed by one of the founding families of this Massachusetts town.

A small and surprising passageway in Saint Petersburg devoted to the Beatles.

A mining town, now abandoned, was built in a canyon so narrow that the railroad ran right through the hotel lobby.

In the early 1900s, hundreds of Black Americans found opportunity in this now-abandoned rural community.

Abandoned businesses, homes, and rusted cars are all that remains of this stopover town.

Ride in 1960s style on the private luxury train Marshal Josip Tito used to travel around Yugoslavia.

At high tide this strange footbridge appears to have no purpose whatsoever.

Part of a secret 1970s nuclear defense program is now open to the public.

Near Birmingham, England three and a half miles of top-secret tunnels housed a World War II “shadow factory” and a Cold War nuclear bunker.

One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.

Strange rock formations tower above the river that snakes through this enchanting Icelandic canyon.

The land is full of geologic eye candy, such as otherworldly spires, mushroom-shaped hoodoos, and prehistoric fossils.

A southern Swedish island is home to the last ERSTA artillery battery, meant to protect the shoreline during the Cold War.

After millennia of erosion by sand and churning water this Brazilian valley now looks like a lunar fantasy.