Once used as a deterrent to drinking alcohol.

A beautiful geyser under environmental threat.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

An architect's childhood fantasy treehouse made real.

One of the last socialist halls still standing in the United States.

A sprawling museum located on the former site of the Orphan Girl Mine.

New fungal and bacterial species call this deadly lake home.

This elaborate towering structure was once famed for its revolutionary height.

A beautiful footbridge with over 2,000 glass sculptures along the walls and ceiling.

A working steam clock, one of only a few in the world, located in Vancouver's Victorian Gastown.

A whimsical sensor instrument for Minneapolitans to play on their walks to work.

The land is home to swimming ponies and a legendary 18th-century treasure.

WWII-era bunkers are hidden under the beaches of this picturesque park, which is still scattered with wartime watchtowers. .

The Dover International Speedway is home to a towering, concrete-skinned, racecar-hungry behemoth.

What looks like a simple quaint estate in rural Pennsylvania was in the 18th century home to a small monastic community.

The oldest farmer's market in America is so ancient it was approved by the King of England.

Berkeley Hot Springs presents to you "the only outdoor monument to presidential bathing."

Maryland's first (and last standing) toll house on America's first federal road established the state as the "Gateway to the West."

The longest covered bridge in Delaware.

The highest point in Delaware is located under a trailer so this marker across the street will have to do.

A blend of art, antiquities, and Americana fill this museum, surrounded by whimsical, enchanting gardens.

This weeping, 10-foot-tall sculpture was a maquette for a 9/11 memorial.

A scenic fort on the harbor protected Philadelphia from an attack that never came.

Downtown Minneapolis mixed art and function by turning some of their sewer covers into works of art.