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

An architect's childhood fantasy treehouse made real.

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

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

The palatial McDonald's that inspired Wesley Willis.

Pizza with a side of fine art.

Each of these gorgeous, intricately decorated rooms is painstakingly crafted to the scale of 1 inch: 1 foot.

Watch the newest land on the planet form before your eyes.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

The Old Courthouse takes visitors on a captivating trip through St. Louis' timeline.

This is not your typical jungle gym.

"We Seceded Where Others Failed."

A monument celebrating the idea of reaching inaccessible places.

Island ghost town detailing Flagler's folly in building the Overseas Railroad.

The former home of the Nobel Prize-winning American writer is now home to dozens of six-toed cats.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

The capital of the Cayman Islands is a center of offshore banking, but gets battered by blistering hurricanes.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

This sprawling concrete suburb of Kraków was designed by the Soviet Union as the model proletarian city.

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

This gem is often wrongly overshadowed by the larger, newer Metropolis church in Athens.

This 15th-century island fortress later served as home to the executioners no one wanted to live near.

Large collection from the 3rd millennium BCE.