These beautiful ruins deep in the Pennsylvania woods are thought to have been a ski lodge or a speakeasy, but no one really knows.

The oldest arched-covered bridge in Virginia has truly withstood the test of time.

Outdoor exhibits explore the contributions of European, African, and indigenous peoples to American frontier culture.

The eerie ruins of a remote abandoned hamlet said to be founded by the survivors of a shipwreck.

One street divides a single town that stands in two U.S. states.

Bubbling up from deep underground is the warm crystal clear water that fills the Warm Springs Pools, America's oldest spa.

The oddly shaped, steam-spewing building is now an art studio and gallery.

Lines from a walking song are etched into a rock in Natural Bridge State Park.

A small Richmond island dotted with the remnants of hundreds of years of history.

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

A mysterious castle built as a monument to lost love.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

Natural rock water slides hidden in the remote forests of northern Idaho.

This once-palatial plantation may have been the site where a draft of the Declaration of Independence was written.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

This maze-like slot canyon is a unique gem within an already fascinating geological area.

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

This general store is more than a century old and home to various oddities and antiques.

The remains of one of the last mining camps developed on the New River.

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

Near-constant high winds deform the trees on Spruce Knob, the highest point in West Virginia.

Take a steam-powered ride straight out of the past on this Appalachian rail line.

This abandoned dream castle and its cemetery look out over the city that once inspired their creation.

This abandoned amusement park was built on a site with a dark history.