See prehistoric footprints, plus two complete mastodon skeletons.

A watercolor recreation of a famous fresco unearthed at Pompeii.

The secret city built by the Manhattan Project.

An abandoned coal mine reached by a steep hike.

One of the oldest and tallest lighthouses still in service on Lake Michigan.

The spaceship-like theater, which is still in use, was one of the most popular exhibits at the 1964 New York World's Fair.

An adorably sweet display of sculpted Precious Moments figurines.

A gorgeous garden oasis with winding paths, stone bridges, and a troubling history.

Fascinating military history, awe-inspiring wildlife encounters, and endless outdoor adventures draw people to this sprawling park.

A mysterious castle built as a monument to lost love.

A building so large that it has its own weather.

The third tallest lighthouse in America once guided author Stephen Crane to safety.

Location of a reliquary containing bone fragments of 18 saints.

Arrr! The most authentic collection of pirate artifacts in the world... matey.

The walls of America's oldest masonry fort famously "swallowed" cannonballs.

This shrine commemorates the site of the first known Catholic mass in the United States.

A real (but thankfully not live) missile stands tall as a monument to the United States military in the small town of Cordele.

A huge railroad museum with over 100 pieces of rolling stock focusing on the railroad history of Pennsylvania.

A reversed traffic signal that was once violently misinterpreted as a statement on British-Irish relations.

The writing studio of an American adventure author, built in the style of a medieval castle.

Lovingly nick-named the "Brick Dick" this municipal tower was winner of the World's Most Phallic Building Contest.

The largest ancient burial mound in Ohio.

Inside houses a vast collection of military aircraft and missiles spanning the ages.

These sub-farmland caves are home to a majestic stalactite known as the "Crystal King."