This former outpost was designed to protect the lucrative fur trade of the 18th century.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

Cave shrine on Monte Pellegrino.

The final resting place of the Emperor of the United States and Protector of Mexico.

The beautiful, ornate weather station is the most popular geocache in Salzburg.

The medieval network of canals hidden underneath the city is opened to explorers each year.

A major spiritual gathering place in central Maine since the mid-1800s.

Despite its extensive history, this fort saw little to no combat.

A shoreline exhibit describing the disastrous first attempt by the French to colonize North America.

This nature mural exists to protect the surrounding environment and its own canvas from destruction.

A showcase of geologic history is home to one of the largest collection of lunar meteorites on Earth.

The “Grand Canyon of Maine” is a three-mile gorge full of striking geological features.

The steel hull of a wrecked tug rests on Lobster Cove on Monhegan Island’s rocky southeastern shore.

For nearly 200 years the same family has harvested ice from a small pond in eastern Maine.

Steam engines and conveyor belts are remnants of a genius system left in the middle of the Maine woods.

A beautiful, water-filled quarry that has become a popular haunt for swimmers and artists.

The debris forms a solemn memorial to those who died in a 1963 accident.

Former laboratory of radical psychiatrist Wilhelm Reich.

Accessible only by boat, this centuries-old island fort never saw troops or combat.

The grave of Mary Nasson is shrouded by witchy legends.

The highest point in Maine is a grand gift to the state citizens that also happens to be one end of the Appalachian Trail.

True to its name, this bouncy walkway may be the world’s smallest suspension bridge.

Civil War Fort on an island in the Boston Harbor.

On a former island, this old fortification once used to protect the Boston Area and started Edgar Allan Poe in his military career.