Detroit’s downtown castle is one of the oldest structures in the city.

A charming remnant of 19th-century fishing towns sits on Michigan’s Leelanau Peninsula.

The park is home to the United States's only still-operating Dutch windmill.

An unlikely beach paradise of giant sand dunes lies between two lakes just a few minutes from Michigan's cherry country.

A Beaux-Arts triumph set to become Ford's innovation campus

After a water tower painting was accused of being an ad, a simple fix was made that gave the city a motto.

The world's longest known cave system.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

The tomb was guarded by soldiers from both sides of the war, and some left their initials carved in the brick.

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

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.

An extensive, if one-sided, history of U.S. law enforcement's war on drugs.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

A favorite of Amelia Earhart, ranking among those rare bridges that can be crossed without changing sides of the river.

Funded by John D. Rockefeller, this is one of the earliest, and most beautiful, shopping arcades in America.

One of the largest Native American shell middens stands 30 feet tall.

This small museum gives visitors a chance to soak up the history of the "sponge capital of the world."

Strange beasts lurking in a garden are all that remain of a quirky, short-lived theme park.

The third tallest lighthouse in America once guided author Stephen Crane to safety.

Meet manatees face-to-face at this zoo for native species.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

The John Snow Memorial marks the epicenter of London's 1854 cholera epidemic.

These ornate arches show how the course of the River Thames has changed.