This outpost of America's most popular fast-food restaurant is housed inside a palatial mansion.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.

This stone incorrectly marks the 35th parallel, causing some territorial kerfuffles.

This museum pays tribute to the Cherokee leader who created a written language for his people.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.

The longest eruption in the history of La Palma originated with this volcano in September 2021.

On Waikīkī Beach, a monument to four extraordinary individuals of dual male and female spirits who brought the healing arts from Tahiti to Hawai'i.

Once thought to be the oldest living tree in the world, Methuselah was germinated before the Egyptian pyramids were built.

The eerie remnants of an ancient forest were hidden under the sand for centuries.

Where monkeys run wild and the humans are caged.

The world's largest occupied bat houses hold hundreds of thousands of flying mammals.

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

The highest point in Washington state is a volcano covered in glaciers.

This century-old confectioner's outlet store was plucked right out of the Seattle World's Fair.

A huge musical sculpture and other art installations on the National Oceanic and Atmospheric Administration grounds.

This quiet neighborhood is also home to a 700-ton rock transported by the last Ice Age.

This remarkable collection devoted to the study of fish includes 1 million preserved specimens from all around the world.

This former Texas landfill is flush with 300 million-year-old fossils, all fit for the taking.

This sacred cavern, 400 feet deep, is home to millions of bats and an ancient burial ground.

A popular swimming hole that hides one of America's most deadly diving spots.

Over 100 million years ago, beach-bound dinosaurs left permanent marks on San Antonio's landscape.