17,400 lbs., 12 feet in diameter, and 29 years in the making.

Half of a waterfall goes into the river while the other half seems to disappear.

This large midwestern cavern features impressive rock formations and an underground waterfall.

Opened in 1956, the first modern indoor shopping mall in the world was inspired by the shopping arcades found in European cities.

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

Triangular House built on a leafy residential street in St. Paul.

This picturesque cliffside beacon no longer calls to sailors but shines once a year in honor of a famous shipwreck.

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

A museum within a museum, devoted to history's most questionable medical devices.

Duluth mineral magnates built this charming art deco lodge to be their private clubhouse.

A treehouse assailed by the elements and the government, now gone.

A tribute to the statues of Easter Island along Route 66.

A rare wayfinding portmanteau of “Street” and “Avenue.”

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

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

A self-built castle made by a mysterious man.

These crudely shaped folk giants may be the the second most photographed statues in the U.S.

This posh mansion began as a family's estate and ended as the site of a murder ripped from the pages of a pulp novel.

The watery grave of an impractical idea.

This rare vessel mixed luxury with labor before being converted to a museum and sometimes haunted maze.

Its collection contains relics from the devastating disaster that set the town ablaze.

Home to the Amorphophallus titanum "Corpse Flower," which is among the largest flowers in the world and also smells powerfully of rotting flesh when in bloom.

This taxidermic smorgasbord was co-created by an artist poached from the Museum of Natural History.

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