A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Eighty million natural history specimens call this gargantuan museum home.

A chain of bells connect the California Missions and honor the legend of the "King’s Highway."

An alley covered with 20 years of bubble gum.

The longest and widest floating bridge in the world.

This grand old 80-foot sequoia towers above the buildings in the city’s retail center.

A 100-year-old purveyor of curiosities, curios, and kitsch featuring mummies, shrunken heads, and a Fiji Mermaid.

A museum dedicated to the history and exploration of both popular music and science fiction.

A guitar mounted on a wall in Temple Bar honors the Irish musician.

A statue in the center of Dublin dedicated to one of their favorite sons of rock & roll.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

A little sculpture with a large wardrobe.

Climb inside an iron crystal magnified 165 billion times its normal size.

A lonely monument to the original Silicon Valley tech campus.

At night, this glittering musical tunnel draws skaters and photographers.

It is locally loved and ridiculed for literally looking like poop.

The headquarters of a secretive order is also a beautifully-designed park.

An extensive collection of ancient Egyptian artifacts and mummies.

The largest permanent Monopoly board makes one of the longest games even bigger.

Guarded by the Angel of Grief, the Stanford family tomb attracts an odd mix of halloween revelry and somber contemplation.

California's largest steel arch bridge.

Hidden in the Santa Ynez Mountains off Highway 154, this tiny restaurant once served as a stagecoach stop.

A replica memorializes the site where women were punished after the last witchcraft trial in Ireland.

These barriers stand as stark reminders of Northern Ireland's troubled past.