A cave interior in the shape of the ancient rhinoceros, created by lava cooling around its carcass.

An exercise in patience and imagination, where Mother Earth turned common stuff into precious hidden treasures.

A short hike into the mountainside forest reveals a decaying 1890s town.

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

This is one really big nut.

Home of the International Space Hall of Fame.

Dig for your own trilobites in this goldmine of invertebrates.

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

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.

This museum started as a collection of Manhattan Projects and continues to add exhibits as they are declassified.

The largest dinosaur trackway in North America is tucked away among this canyon's ghosts and archaeological gems.

This prison-turned-museum is a remnant of the Old West's grizzly, violent past.

The superstar of Cold War nuclear bunkers has been featured in countless films but is now barely operational.

Victorian "Fancy Craft" Hair Wreaths and Relics.

Curios, scientific antiques, oddities for sale.

At this Denver landmark, the meals are compulsory, the sopapillas are complimentary, and the insanity is everywhere.

Once a mortuary that held the remains of Buffalo Bill, this Denver hotspot is now a death-fixated restaurant.

This landmark cemetery in Boston was created more than 300 years ago.

The American Revolution was galvanized into serious action due to the tragic clash with British soldiers that occurred at this location.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

19th-century operating theatre in which the use of ether was first demonstrated - plus, a skeleton and a mummy!

A beautiful Victorian-era cemetery, complete with a miniature village.

This Boston medical museum features the skull of the famous medical case of Phineas Gage.