An architect in Aspen used psychedelics as his muse while building this mushroom masterpiece.

A unique attraction and museum dedicated to exploring iconic roadside structures.

A large instrument played by the wind.

The highest dunes in California are the most likely place in the area to hear the Singing Sands.

This former Masonic hall has been turned into an art project that uses even more metaphysical iconography.

A sculpture for the sun and stars, created by Nancy Holt.

Native Americans built this circle of stones, which was used to predict astronomical events.

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

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

A beautiful oddities shop crammed with strange and morbid curiosities.

An ice cream parlor chain that caters to vegans and pinball fans equally.

An enormous pink granite batholith, long attributed with spiritual powers by the Tonkawa Indians.

A 90-year-old underground water reservoir offers a more industrial kind of tranquility.

An earthwork sculpture built by Robert Smithson in the Great Salt Lake only reemerges during drought.

Giant origami sculptures tucked into desert scenery beckon passers-by to explore further.

This rare example of a "tidefall" is a spectacular drop from the cliffs down onto the beach.

A tiny red pebble marks what may be the quietest outdoor spot in the United States.

Ancestral Puebloan ruins, natural arches, and box canyons abound in this seldom-visited corner of Monument Valley Navajo Tribal Park.

The only diamond mine in the world where you can keep what you find.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Shop of curiosities with a dinosaur museum tucked in its basement.

A half-mile long and three stories high, this bridge over the Des Moines River Valley mimics a descent into a mine shaft.

Sniff the Titan Arum's rotting flesh.

Who needs fancy modern water slides when this giant North Carolina rock works just as well?