This shale formation along the Appalachian Trail once inspired the third president of the United States.

Home to the largest urban bat colony in North America, estimated at 1.5 million bats.

A mechanized clock where a man fights off a dragon, crab, and rooster.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

Order scoops of pandan, lychee, and black sesame at this family-run institution.

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

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

The stones that traveled from Spain to eventually become a holy place for San Francisco's nature worshippers.

One of only two commuter aerial tramways in the United States.

This New England covered bridge is home to the tale of a jilted lover known to haunt the area.

The narrowest house in America is seven feet of pure spite.

This metal eagle one of the final remnants of a newspaper that wanted to keep Brooklyn to Brooklyn.

A century-old magnolia tree is the only living landmark tree in New York City.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.

Sit where JFK proposed to Jackie or where Nixon dined on meatloaf at this storied pub.

Architecture lovers won’t stop touching the National Gallery's 19.5 degree marble prow.

The "lovely red Vega" of the legendary record-settling pilot.

A haunting tribute to pioneering photographer Clover Adams.

The house where John Wilkes Booth conspired with his co-conspirators.

An Industrial Revolution-era public work that purified water using nothing but sand.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.