The first declared National Monument in the United States.

The only road through the heart of Glacier National Park.

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

A beautiful geyser under environmental threat.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A rare chance to get up close and personal with a 13-mile ribbon of ice near downtown Juneau.

The first bridge observation tower in the U.S. offers one of the best views of Maine.

This 19th century granite fortification is one of the most well preserved forts in New England.

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

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

These crudely shaped folk giants may be the the second most photographed statues in the U.S.

An island filled with hundreds of hanging, decomposing, decapitated dolls.

Gilded heaven for philatelists and architecture freaks, still in full working order despite sitting atop tremulous ground.

This church, buried halfway in lava rock, is all that remains of a Mexican village destroyed by a volcano.

High atop a Mexican rainforest mountain, this ancient pyramid once drew pilgrims countries away.

Inspiring Herman Melville and Henry David Thoreau, Mount Greylock in western Massachusetts is the highest point in the state at 3,491 feet above sea level.

"Holy Wisdom" overlooks the city that became its namesake.

A striking symbol of the Bulgarian capital.

The oldest Italian café in Boston, this spot also serves as a veritable museum of vintage coffee ephemera.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

This imposing tower named after the mythical sword of King Arthur is considered the tallest freestanding climbing wall in the world.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

A mysterious stone embedded at the base of a historic Boston building.

Two thousand artifacts from around the world collected by one woman who loved to travel.