A tunnel that brings more than a century of history to life from the deepest parts of the Niagara Gorge.

This impressive working clock made of 16,000 plants changes its flowers twice a year.

The world's longest known cave system.

A life-sized recreation of the megafauna that once roamed this region is a feature at the birthplace of American paleontology.

One of the last few period-correct, hand-operated canal locks in the country.

A circle of giant painted vases in the former pottery capital of the United States.

This building contains handprints that are well over a century old.

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

Despite its lavish ornamentation, and wholesome lifestyle of its devotees, this mountain commune has faced its share of issues.

One of the oldest surviving lock houses on the Ohio River.

This former tuberculosis treatment facility now stands at the center of a public park.

The remains of a massive blast furnace in what was once one of the country's largest iron-producing regions.

Locals call this magical moss-covered walkway the "Emerald Path."

For decades, it has disappeared and reappeared as water levels rise and fall.

An unassuming 13-acre park is home to over 12,000 roses.

Where the oil industry began.

Antiques and recycled art surround this cabin designed to resemble a 19th-century schoolhouse.

There is beauty and history in the ruins of this former company town.

An American flag was erected for every day that passed during the Iranian Hostage Crisis.

The overgrown remains of an old rail bridge rise above the valley like ancient Greek ruins.

Smoky, also known as "Yorkie Doodle Dandy," was a four-pound hero of World War II.

One of the few surviving examples of the first lock and dam system built on the Ohio River.

In the middle of an abandoned stretch of old Route 50 lies a tombstone that weighs three tons.

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