San Francisco's oldest operating hotel, with a Victorian atmosphere and a "haunted" fourth floor.

The giant pair of sexy legs sticking out the window of this costume store have become its main draw.

A monument to the love people have for their pets.

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

The randomness of this wall of lava lamps helps encrypt up to 10 percent of the internet.

This private residence was the template for one of the most beloved television homes of all time.

The remains of a ruined mansion memorialize the 1906 earthquake.

The oldest burial ground in the city, final resting place of city founders, Ohlone natives and murderers alike.

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

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

Visible below the waves are memorials to the city's Gold Rush dead.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

A tiny theater hidden in an alley plays a constant stream of short silent films for anyone willing to peer through the peephole.

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

Relics of the 1894 Midwinter Exposition continue to delight visitors today.

Get lost in this haunting fairytale art walk through a man-made eucalyptus grove.

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

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.

This secluded walking trail is a hidden gem of a Pittsburgh park.

This spot memorializes one of the greatest plays in NFL history, unless you happen to be a Raiders fan.

A giant ball made from pieces of an old Jeep.

The largest clock face in the United States is twice the size of Big Ben and infinitely more ad-sponsored.