Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

Indiana's greatest rare bookstore has a special shelf for Hoosier authors.

A theme park featuring a replica of Noah's Ark built to the measurements specified in the Bible.

Florida castle built with aluminum printing plates.

This Florida sinkhole hides a rainforest-like micro-environment in its depths.

A 10-foot segment of the concrete barrier stands quietly on the campus.

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

Once decrepit and slated for demolition, now one of the longest pedestrian bridges in the world.

This historic train station has been converted to a locomotive themed hotel.

Explore the wide world of miniature trains.

The world's largest private aircraft collection.

A haunted hill that supposedly defied gravity.

It's believed Elvis Presley was inspired to write his breakthrough track after staying here.

A replica of one of the more than 15,000 civilian lookout towers that lined the U.S. coast during World War II.

A building so large that it has its own weather.

Despite being made of a seashell mortar, the crumbling remains of this historic Florida mill are still standing.

These mysterious ruins are hidden amid this sleepy coastal city.

An aviation relic that made coast-to-coast travel possible.

One of the largest Native American shell middens stands 30 feet tall.