A dedication plaque on this Boston tunnel is a microcosm of a massive, controversy-laden construction project.

In this quiet park a rendition of a classic painting graces the outside of a charming restroom.

This is the last hand-cranked chain ferry of its kind in operation in the United States.

Dating back to the 1800s, two imposing buildings in Michigan have had countless transformations over the years.

The Old Courthouse takes visitors on a captivating trip through St. Louis' timeline.

Speak to a companion on the other side of the room loud and clear through this architectural anomaly.

This recently restored timepiece has stood all around Kansas City.

A crumbling stone stable and carriage house are all that remain of a manse that was once filled with Egyptian artifacts.

A 19th century hat factory still stands as a crumbling ruin in upstate New York.

Original factory of John G. Borden who started what we know today known as Borden Dairy.

The souvenir got the company’s founder out of a pretty pickle at the World’s Fair.

There aren't too many operational funiculars around, but Pittsburgh has two!

The only way to see Pittsburgh is from the top of this lookout point, just like the ancient members of the native peoples did.

This church in Pittsburgh is home to the largest collection of religious relics in North America.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

Fresh wooden posts have been added to ancient holes to recreate a primitive henge clock.

Quirky water tower advertises the long-gone Brooks Tomato Products Co.

The mysterious wonder of an underground waterfall is illuminated by multicolored lights.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

Enormous lake at the bottom of a unique cave system.

One of the few surviving "Wigwam"-themed motels.

The world's longest known cave system.

These faux-cliff dwellings allow visitors to climb around on a replica archaeological site.

The highest bridge in America was built for an almost unnervingly small amount of money.