This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

This artistic fountain display pays homage to this area's theatrical history.

The murals have transformed a residential alley into a vibrant drive-through gallery.

A stack of stones steeped in Irish folklore, much like the hero they're connected to, hide in plain sight.

An exquisite tunnel of cascading flowers.

A network of concealed passageways lies within a busy London Underground station.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

An experimental, automotive replica of Stonehenge.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

A striking sculpture built to honor the women of the Lakota and Dakota Nations.

An open-air, roadside eatery celebrating a historic indigenous cuisine of complicated significance.

Something about this Brazilian city is slightly askew... literally.

Edinburgh’s version of the Sistine Chapel is this former church, with an interior covered in paintings done by one woman over the course of nearly a decade.

Mysterious rocks that ring musically when struck.

Stockholm's last remaining paternoster elevator.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

The cliff and rock formations are made out of Sioux Quartzite.

The atmospheric road was never meant to be so creepy.

Narrow gorges and deep pools created by long-ago glaciers.

You can cross from one country to another in a single hop on this little bridge.

All of Chicago's wood-paved streets are long gone but two alleys remain.

The absurd creation is a compulsory destination for selfies in Buffalo.

Red sandstone structures dominate this landscape, which has been inhabited for some 5,000 years.