Europe's largest prehistoric mound – burial site of a legendary king?

The largest stone circle in the world has ended up bringing up more questions than it has answered.

Part museum, part piece of Arthurian-inspired history, this stately hall attracts King Arthur fans from miles away.

A unique waterfall that some believe attracts the fairfolk.

A fantastic castle rumored to be the birthplace of King Arthur.

This naturally heated mountainous creek has created a group of neon blue pools of potentially deadly boiling water.

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

A beautiful geyser under environmental threat.

The first declared National Monument in the United States.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

One of the few remaining carousels built by master amusement park carver Charles I.D. Looff.

The ghostly remains of an accidental sea.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

Why have you never heard of the second most popular tourist site in New York?

A classically inspired temple in Redwood City.

This controversial depiction of the "Founder of California" looks as though it was sculpted from mashed potatoes.

Once close to extinction, there is no shortage of elephant seals on the beaches of Año Nuevo State Park.

A "gravitational anomaly" located in the redwood forests just outside of Santa Cruz, California.

Home to the "Circus" trees created by Axel Erlandson.

From the Difference Engine to the Cray-1, all under one roof.

The world's first permanently occupied mountain-top observatory continues to report on the stars.

This giant shopping mall still holds signs of its automotive past.