Thanks to modern navigational tools we now know that the true prime meridian runs through a park next door.

19th-century scientists would make the pilgrimage here to verify the precision of their measuring sticks.

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

One of the most scenic falls in Massachusetts has a history of death and grim legend.

This giant rock arrived at this quiet park thousands of years ago on the back of a massive glacier.

The poet's been ambling through these New York woods since 1940.

The rare American Civil War-era weapon was never fired in anger.

Once America's longest-manned military fort, now an abandoned hulk.

The US Navy's only submarine museum is also home to the world's first nuclear submarine.

Holding multiple historical boats and an entire 19th century village, this New England attraction is the largest maritime museum in the world.

This small-town pizzeria won the Hollywood lottery.

On a small Slovenian island, diners can mix and match a classic cake into dozens of sweet and savory flavor combinations.

A clone-tree in Washington Square Park sprung from seeds that went to the Moon and back.

The world's third-largest crystal sphere has sat in the Penn Museum since 1927 with the exception of one outlandish theft.

Overlooking the Colorado Convention Center is this giant sculpture made from thousands of triangles.

A Rocky Mountain city provides a happy ending for a pinto pony and his Brobdingnagian red chair.

In the middle of a busy airport, a statue honoring the astronaut who told Houston that Apollo 13 had a problem.

The spot in the Mile-High City that's exactly 5,280 feet above sea level (at least for now).

This landmark building is now a vibrant performing arts space with musical acts from around the world.

Dedicated to the art and science of glass in equal measure, this space is as much laboratory as museum.

This exhibit allows visitors to wander through the interior of a replica Ice Age glacial cave.

Pluto is still considered a planet in Ithaca, New York.

It would take 35 firetrucks to fill this enormous glacial pothole.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.