A tribute to a Ukrainian heroine who went undercover and killed several Nazi operatives.

The ruins of the northernmost pueblo in the Americas tell the story of a mixing of native cultures.

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

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

Franciscan monks created a facsimile of the Holy Land for North Americans who couldn’t afford the trip overseas.

This beloved Baltimore spot features caged dolls, a giant Pez collection, and many, many mannequins.

Eighteen miniature death-scene dioramas.

A former sanitarium where soldiers were sent to recover in the healing waters of hot springs.

This underground cave located in the most barren reaches of Idaho is filled with ice year-round.

This set of hot springs also comes with fantastic views.

A petroglyph map of the upper Snake River carved by prehistoric hunter-gatherers.

During the solar phenomenon "Lahaina Noon" this bendy, curvy sculpture forms a perfectly circular shadow on the ground.

A massive underwater sinkhole made famous by Jacques Cousteau.

Volcanically heated hot springs.

Hidden deep in the Guatemalan jungle is a turquoise paradise of natural pools, caves, and waterfalls.

For centuries, this town's hot springs have been embraced by rich and poor—and even by Popes.

The longest living non-clonal organisms on Earth.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

The highest peak in Puerto Rico is home to a rare fern that can only be found on six trees at its summit.

The highest point in South Carolina was once owned by an energy company that neglected it but now the state is taking it back.

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

The highest point in Mississippi is a hilltop that was once used to bombard a nearby town with artillery.

The highest point in Maryland is only accessible by hiking through another state.