This ruined fort hidden at the top of Central Park can't seem to keep from losing its historical plaques.

Reverend Jen's unique museum/living room showcases her troll collection.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

These unassuming lighthouses have seen the first reading of the Pledge of Allegiance, the first wireless transmission, and more than one mystery.

An 18th-century Spanish watchtower made entirely of seashell and concrete.

This 1830s store is believed to be the site of Harriet Tubman's first stand.

World War II bunker still standing on the New Jersey beach.

New Jersey's last historic covered bridge was rebuilt from pieces of the original 19th-century structure.

A historic grist mill and active sluice on the Black River.

This picturesque ghost town is located on the banks of the Suwannee River.

The ruins of this antebellum sugar plantation are the end result of a Seminole attack during the Florida Wars of 1836.

It's a pretty creepy lock-up.

Two men built this castle on the Florida coast as an artistic “landscape sculpture.”