A mysterious castle built as a monument to lost love.

The famous boat that once ferried Bogart and Hepburn still floats in Key Largo after being abandoned for years.

This spiny beast guards an artist's village while vying for the title of largest lobster in the world.

Bat house that has only ever housed bat for one night; they all flew away and never came back.

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

An idyllic swimming pool tells the tale of Hemingway's trouble with women.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

A monument celebrating the idea of reaching inaccessible places.

One-time winter retreats of prolific inventor Thomas Edison and his friend Henry Ford.

Home to Hollywood history and a very special salt crystal.

The largest self-built castle in the U.S., six decades in the making.

Home of Howard Hughes' Spruce Goose.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

The ghostly remains of an accidental sea.

Site of the first official transatlantic wireless communications.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

America's post-nuclear-attack chambers of Congress.

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

An enormous warehouse filled with parade floats collected from over 50 years of patriotic celebrations.

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

The world's largest fully steerable radio telescope.

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

The site of the climactic scene from the classic horror film is now a historic landmark.