The largest treasure hoard in Europe is contained in a castle that was bombed out during World War II.

This once-popular otherworldly landscape was formed by one of the largest volcanic eruptions in history.

A lonely monument to the original Silicon Valley tech campus.

A serene desert oasis speckled with ancient artifacts.

Historic, 19th-century wagon wheel ruts cut into soft volcanic ash.

The longest manmade tunnel in Queensland is now a beautiful trail, home to a special colony of bent-wing bats.

This ancient walled garden turns fog into food.

A painting in the historic Cathedral Basilica depicts Jesus and his disciples dining on a traditional Peruvian menu.

An overlooked marble is the only surviving in-place 18th century example of the measurement that changed how we define distance.

A former factory serves as a shrine to the industry that sustained Santorini for decades.

Rumored to have been frequented by Vincent van Gogh, it's the only remaining genever producer in the Hague.

This domed temple was built in a hidden cave mouth as a refuge for sinners seeking absolution.

This modern monument to pagan belief looks like it was transported straight from ancient times.

A lovely aquatic park built by a one-armed Civil War veteran who made a fortune from lotuses.

Deceased nuns were placed on stone chairs to decompose, while the surviving nuns prayed near the lifeless bodies.

On the Oregon coast there is a natural hole that seems to be draining the sea.

An acoustic anomaly with a mysterious cause.

A KFC honors an eighth-century Chinese poet with holograms and verse.

The Swiss artist's bulbous and overgrown shape-shifting sculpture controversially graces the center of Bern.

A massive work of modern art that appears to be a crop circle in the middle of the desert.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

A popular 19th-century natural landmark is now hidden within a sprawling forest.

This medieval sanctuary's tree-framed door looks like a portal to a mythical realm.