Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

The final resting place of the first documented Chinese person in the United States lies in a Boston cemetery.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

American revolutionaries and British soldiers alike are buried here in the fourth-ever cemetery in Boston.

A men’s restroom became a sandwich shop.

One of the last remaining World War II Victory Gardens in the U.S. is quietly growing across from Fenway Park.

Its collection includes a broad array of social, geographic, graphic design, and political history.

This coffee shop lies hidden beneath a historic church.

This London pub hides a peculiar secret: a recreation of the rooms shared at 221b Baker Street by Sherlock Holmes and Dr. Watson.

This ancient oak plays host to carvings of magical elves, gnomes, witches, and other creatures prominent in local folklore.

You'd never know the houses at 23-24 Leinster Gardens were fakes—until you see the train tracks on the other side.

Home of one of history's most famous cartoonists just as he left it.

This hidden rooftop garden in downtown London offers a quiet respite from a bustling city.

A mysterious carving from 17th-century London seemingly depicts a young boy sitting on a bread basket.

The bridge is a secret gallery of discarded gum that has been transformed into miniature masterpieces.

A wall of chewing gum moonlights as collective art.

A rotting tree in the middle of Seattle doubles as an elaborately-controlled art piece.

This sculpture forces visitors to confront their relationship with space.

A community gathering place that once housed half-ton tanks and the World's Fair.

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

The Denny Substation has been called "the coolest substation in the world" and sits in a densely populated Seattle neighborhood.

The four tall pillars once marked the entrance of the historic Seattle church that fought for women's suffrage and civil rights.

42nd story Pyramid shaped penthouse tops Seattle's oldest skyscraper.

A replica that won't float away.