Once a speakeasy operated by Al Capone, this Milwaukee cigar bar is now a haven for ghost hunters.

This was once the largest four-sided clock in the world (yes, even bigger than Big Ben).

This holy goods emporium is where priests go for a little retail therapy to outfit their churches.

This storied music venue was once a tavern that housed an Italian Anarchist book club and prohibition parties; today it's a community space for artists and musicians.

Where three rails and three centuries of transportation meet.

A small park honors the legendary Ukrainian poet.

The last remains of one of the oldest and largest oak trees in the United States calls this state park home.

A small ballpark on Maryland's eastern shore pays homage to its favorite son, the most fearsome home run hitter of the dead ball era.

Both the building and blades of this reconstructed 19th-century windmill can turn in a breeze.

Once used by British troops to gather water prior to the Battle of Bladensburg.

A historic Maryland home that once belonged to a man who has been called "the most insignificant" U.S. Supreme Court justice.

On the side of a Virginia highway, a collection of monuments commemorates an 18th-century trek through the Blue Ridge Mountains.

Herbert Hoover's "Brown House" rural presidential retreat was a PR disaster amid the start of the Great Depression.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

The most magical part of this Latin American and Caribbean art museum is a room covered in beautiful blue tiles from floor to ceiling.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

Where the U.S. government kept its actual treasure, before Fort Knox.

Literal "money laundering."

The lost library of Alexandria, revived as a spearhead of cultural preservation.

A small but very fascinating fountain in the center of Rome with four books and a deer carved.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

This historic mansion was built as a symbol of love between a husband and wife.

After James Madison's death, his wife and former First Lady Dolley Madison lived in this yellow building near the White House.

This rowhouse doubles as one of the most photographed spots in the nation's capital.