A 1,100-ton train fell through the floor in 1953. Workers got it patched up in just 72 hours.

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

Once America's tallest structure, now a Baltimore landmark.

A granite monument honors a beloved World War II canine mascot.

Where the embers of the Big Bang were first detected.

Once at the center of U.S. finance, the historic Trading Room was meticulously recreated piece by piece and rebuilt in the Art Institute.

Commercial airplanes land mere feet over the heads of sunbathing beachgoers on this tiny island.

A gigantic 10-foot tall stone man.

Why have you never heard of the second most popular tourist site in New York?

A winding, cliffside stretch of road overlooking the Delaware River.

One of the U.S. Forest Service's only mansions is outfitted with a dinner table for floating food.

The remains of a community that was forced to move for a dam that never materialized still rot in this Pennsylvania park.

Oldest existing wire suspension bridge in the United States.

"A hideous albatross in the Hudson River Valley."

100 massive sculptures in the Hudson River Valley.

Little Red Lighthouse under the George Washington Bridge.

Visit the monolithic tomb of America's most famous general.

This castle-like building in Manhattan helped destigmatize cancer in the 19th century.

Captain America, Sub-Mariner, and the Human Torch were all born in this art deco Manhattan masterpiece.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Cryptic messages embedded in the New York City sidewalk.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

The most confusing clock in New York.

This Fifth Avenue church has long been the favored worshiping place of Broadway actors and vaudeville performers.