An abandoned saucer-shaped monument in the Bulgarian mountains.

Ruins of a German Castle on top of a towering stone pillar.

This futuristic German spa allows visitors to float in a pool of salt water while zoning out to underwater techno.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

A labor of love built by local hang-gliding enthusiasts, this ideal launch spot was outlawed by the authorities and has since been largely abandoned.

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

The highest point in Virginia can only be reached by passing through ponies and flowers.

North Carolina's finest examples of Native American pictographs have survived for 5,000 years.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

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

Resonating tubes make music from highway overpass.

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.

Reclaimed by nature, the ruins of Doodletown, New York are remnants of a town consumed by a state park.

Six peaceful acres in a residential neighborhood dedicated to art and peace.

The highest point in New Jersey is marked by a massive, if simply named, obelisk.

Whimsical artist house in the New Jersey woods.

This park contains a number of standing stones meant to heal and inspire.

In which a local geological marvel becomes a quaint roadside attraction.

An indoor miniature village and labor of love for Laurence Geiringer, a model railroad enthusiast.

A local prank turned town icon.

A museum dedicated to the history & joys of the trail & your best chance to see hikers throwing up ice cream.

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

This 150 foot seven-tiered cascading waterfall is one of the hidden gems of the White Mountains.

The highest point in the state of New Hampshire, and while unlikely "the worst weather in the world," it sure seems that way to hikers.