Two New York rooftops are home to the largest rooftop soil farms in the world.

A hand-built folk art installation covered with messages of God's love.

A meditative space out of a fantasy story.

California's oldest wind harp represents a historic piece of America's Danish history.

In Coyoacán, a pair of coyotes crown a public fountain in reference to the ancient Aztec name of the borough.

A garden in Lisbon filled with giant porcelain creatures.

Located in the thermoelectric factory that once powered the entire city, this Portuguese museum is shockingly fascinating.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

An early Portuguese serial killer's head is alarmingly well preserved in a jar at the University of Lisbon.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

The world's oldest bookshop still in operation.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

Named after a legendary garden called Eram in southern Arabia, built by order of Shaddad, an Arab king who wanted to compete with Paradise.

A dreamy mausoleum honors Persia's most famous poet.

Mirrors and glass shards cover every inch of this arrestingly beautiful mosque.

A spectacular rainbow of stained glass makes the "Pink Mosque" one of the most beautiful in Iran.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

A hidden bathhouse in one of Stockholm's oldest and busiest neighborhoods is open to anyone who can find it.

The world's largest model of our planetary system.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

Manhattan’s Battery Park has a whimsical carousel full of spinning, glowing fish.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

A 140-year-old castle with underground caves hidden in San Francisco.

An emerald-green grotto just a short trip from Austin.