This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

A stately palace has been converted into the world's largest cannabis museum.

Week-long block party becomes a competition for the best decorated street.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

An art supply shop holds the secrets of this quiet neighborhood's raucous Barbary Coast past.

A speck of nature and art in one of San Francisco’s most notorious neighborhoods.

San Franciscans leave gifts and messages for the magical beings that live behind the tiny, mysterious door installed on a tree in Golden Gate Park.

Nuclear waste dump site now an environmental sanctuary.

A Barbary Coast watering hole built into a Gold Rush shipwreck.

A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

The remains of a ruined mansion memorialize the 1906 earthquake.

A 300-ship graveyard, with a few still visible at low tide.

A nondescript building that's been functioning as a speakeasy for nearly a century and a half.

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

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

A psychedelic labyrinth on the San Francisco bay.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A huge musical instrument played by the ocean.

A wild annual race in Sardinia re-enacts Constantine's victory in Rome.

Windblown rock formations in an ancient Roman quarry.

An Italian vineyard invites religious pilgrims to stop by 24/7 to get their drink on, for free.