A downtown park built on top of unclaimed graves.

A rough granite monument marks the spot where Europeans first caught sight of the San Francisco Bay.

A trail weaves through the verses of a poem illustrated by stone sculptures inspired by Native American pictographs.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

Olfactory delights in San Francisco's Botanical Gardens.

A winding path built in secret on the edge of the continent.

Take shelter from Hawai'i's tropical heat under the massive canopy of largest Banyan tree on the island.

A tunnel of hardened lava along Maui’s famous Road to Hana.

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

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.

The longest and widest floating bridge in the world.

An old vending machine serves up unpredictable beverages from its seemingly magical insides.

This automated sculpture of two men peeing will spell out text messages with their micturition.

This walkway is so narrow it needs its own light to stop pedestrian traffic jams.

Countless grotesque faces stare out from this eerie Prague art wall.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

A surreal statue honoring Prague's favorite literary son.

The hidden lair of an alchemist rediscovered in a 2002 flood.

A 400-year-old mummified arm dangles from the ceiling of St. James the Greater, serving as a warning to thieves.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

Macabre astrological automaton clock dating to the late 1400s.

Cold war icon and onetime "hole" in the iron curtain.