The semi-reclaimed ruins of this canal were once part of an ambitious plan to reroute the mighty potomac.

The world's longest known cave system.

This replica of the Greek structure is in the heart of Nashville.

This rare vessel mixed luxury with labor before being converted to a museum and sometimes haunted maze.

The maritime museum that boasts the largest nautical library in the western hemisphere.

Headquarters of the legendary clairvoyant's readings, spiritual hospital, and massage school.

Scenic mount trashmore, Virginia Beach's most curious waterfront still has a couple of secrets.

America's second-oldest brick baseball stadium was home to a legendary WWII series that only sailors got to see.

This old-fashioned carhop restaurant gave the world the waffle cone.

Three and a half miles of cliffs, rocky beaches, Gilded Age mansions and 40 Steps to nowhere in particular.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

A beautiful maze marks where three countries meet.

This simple stone memorial remembers a secret, Geneva Convention-defying interrogation base from WWII.

This former Nazi castle was built as a school to train what would have been the future of the Third Reich.

The hide of Stonewall Jackson's equine sidekick is on display not far from where the ashes of his bones are buried.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

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

Edgar Allan Poe's old dorm is now a shrine to the author's legacy.

Auburn's iconic eagle flight goes back to a 19th century eagle that dropped dead on the field after inspiring the football team to victory.

The largest freshwater lake in the Florida Keys.

Rumored to be the famed pirate's lookout tower, this historic stone structure is now just watching for tourists.

A petite white lighthouse perched on the ancient core of Stromboli Volcano.

A volcanic old faithful, Stromboli has been erupting continuously for the last 2000 years.

The world's most active stratovolcano is almost always erupting.