This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.

A classic roadside attraction on Vermont's historic Route 5.

The 40-foot-tall votive candle is the largest of its kind.

This iconic water tower and failed bandstand is open for panoramic views once a year.

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

This secret gem of a toy store houses a rideable carousel populated with fantasy animals.

A toweringly silly piece of modern art has been delighting locals since the 1980s.

Hub of Scandinavian culture in a Minneapolis deli.

The Midwest's reigning king of surplus stores is full of nothing you need and everything you want.

When flour explodes, it's not a pretty sight.

Secret hideaway for an alternative beach experience.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

20,000 pieces in a Frank Gehry-designed building.

Every plane, auto, and bicycle in this collection is kept in working order and are regularly demonstrated to the public.

Turns out you can see the world without ever leaving Maine.

The eccentric mansion of one the most popular horror authors of modern times.

A 200-year-old building in the French Quarter that was to be Napoleon's home in the New World.

Florida might be at its most surreal in this museum devoted to the famed Spanish artist.

This impressive Boston holy house is the American mecca for Christian scientists.

An enormous, inside-out glass globe built in 1935.

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