One of many reminders of Tesla's scientific contributions overlooks the falls which inspired him.

Known as the "Cross At The Crossroads," this massive metal cross is just short enough to avoid the FAA.

The first declared National Monument in the United States.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

A fitting attraction for the corn capital of the world.

Elaborate drama imparts an appreciation for 19th century hardships.

A winged-helmed, sword-brandishing tribute to German Americans.

This massive roadside mascot was the first version of the giant to illustrate his butt.

Ever wanted to can Spam?

A pop-culture attraction outside of Dyersville, Iowa, hits a home run.

Decommissioned experimental solar facilities that pioneered solar energy technology.

This giant temperature attraction created some giant electric bills.

A house carved into a rock in the 1940s.

Oddly shaped rock formation, misassociated with a nearby utopian community.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

Pensacola's UFO home has withstood many hurricanes—just as the experimental 1960s design intended.

One of the only Florida forts to remain in the hands of the Union all through the Civil War still stands as a historic stronghold.

A sealed test tube said to hold Thomas Edison's dying breath was given to the inventor's friend and mentee, Henry Ford.

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

The small town of Poulsbo in Washington state is the next best thing to the Kingdom of Norway.

The rusting remains of the largest assembled WWII fleet on the West Coast.

One of the largest free-standing structures ever built, this dirigible hangar is now simply a giant skeleton.