This unusual lava tube spouts seawater during high surf.

The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.

Doris Duke's lasting collection of Islamic Art, hidden in a Hawaiian paradise.

This legendary urban waterfall creates a dazzling display of rainbows.

Climbing this abandoned railway leads to breathtaking vistas of O‘ahu.

This museum housed in a former brothel explores the past and present of sex work in Amsterdam.

A moving memorial to the fallen and missing from WWI trenches.

One of the two original gateways into the Kasbah, this gateway is a nesting site for storks.

God's Saharan sandbox of wrath.

A fortified city, home to a remaining population of five families

One of the most spectacular canyons in the world.

The largest madrasa in Morocco once housed more than 900 students within its exquisite walls.

Fortune tellers, snake charmers, poets, and storytellers all gather on this historic square in Morocco.

It took 40 years to build this Eden-like garden in Marrakech, later restored by Yves Saint-Laurent.

The historic building's ornate stained glass fixture has survived the devastating 1906 earthquake, ensuing fires, and multiple redevelopment attempts.

A hidden gem, named after a San Franciscan icon, offers spectacular views of the Pacific Ocean.

Lombard Street may be more famous, but this is the real “crookedest street in the world.”

The oldest lawn bowling club in the United States.

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

San Francisco’s century-old Christmas Tree.

Shoot for par over the bodies of the dead on this cemetery-cum-golf course.

A modest reminder of treacherous waters at the Golden Gate.

Part mural and part sculpture, this work of art sits in the middle of the Promenade, as if swimming in a river of asphalt towards the ocean.

A shining, cold, black organ lies in San Francisco's financial district.