A vertical tube that allows you to see what's going on underneath the Antarctic sea ice.

Evanston's historic railroad complex saved this rail town from reaching the "end of the line."

An eerie ship cemetery with gunfire as a soundtrack.

This cannonball embedded in the side of an Edinburgh house once served a surprisingly pedestrian purpose.

Near the former site of numerous witch burnings, this lavish Edinburgh mainstay pays homage to Scotland's brutal history.

360° views of the city plus five floors of optical illusions and hands-on science.

Also known as the Great Mosque of Damascus, this is one of the world's largest and oldest mosques.

Created by a local artist, these quirky sculptures each have their own names and personalities.

When it opened during the final years of the embargo, all the drinks and cigars were free.

Part of a WWII submarine is lurking outside the Washington Navy Yard parking lot.

A nostalgic bibliographic gem.

This groundbreaking 16th-century map is known as "America's birth certificate."

One of the three perfect vellum copies of this historic book known to exist is on display in a specially-designed case.

A fantastic array of trays and cables once whisked books over to the Capitol at 600 feet per minute.

An ear-piercing buzzer calls lawmakers to a vote with a series of long and short rings to form coded messages.

This statue of the "father of television" stands prominently in the United States Capitol.

The institution is sitting on a goldmine of 21,000 paints, varnishes, pigments, and primers preserved for posterity.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

A historic neighborhood church is reborn as a psychedelic arts collective.

A street in front of NASA's D.C. headquarters has been named in honor of the Black women who were essential to early spaceflight.

Fittingly, America's museum of architecture is itself a magnificently designed old building.

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

The fountains of the U.S. Navy Memorial are annually salted with water from the Seven Seas as part of a nautical ritual.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.