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

The Burnside Fountain and its questionable interpretation.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

This public square capitalized on a single Eagles reference to bring some life back to an Arizona town.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

This constitutionally sound Muffler Man harkens back to the days these attractions were a must-see.

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

It's easy to see why this eclectic architectural wonder has been dubbed the "Spaceship House."

One of the largest helium balloons in the U.S. is a 112-foot ginormous orange.

This enormous World War II relic is one of the largest wooden structures in the world.

This elaborate towering structure was once famed for its revolutionary height.

The first American department store, and home to the largest operating musical instrument in the world.

The sounds of the world's largest fully functioning pipe organ dazzle shoppers at a Philadelphia Macy's.

The only surviving 19th-century water-powered mill found in the Washington, D.C. area.

The former home of the man whose radical ideas changed the nation.

This twice-relocated "Usonian" home is among the smallest built by master architect Frank Lloyd Wright.

This train station inspired the name of a 1970's rock band and provided the backdrop for their album cover.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

The massive, incredibly rare instrument is over 11 feet tall with a range so deep it goes lower than humans can hear.

This museum sits on the site of a decommissioned military communications base.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

One of the world's most definitive collections of musical instruments, spanning all cultures and historical periods.

A museum dedicated exclusively to aircraft used in the military.

This statue is dedicated to Grace Sherwood, the last person in Virginia to be convicted of being a witch.