Quite simply the largest tree in the world (by volume).

The largest earthwork effigy in the world.

This semi-secret garden in south Seattle emulates a traditional Japanese garden using the plants of the Pacific Northwest.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

Giant, natural amphitheaters made of delicate geological formations called "hoodoos."

Once the most densely populated place in the world, this island is now a ghost town.

No one knows how this Pacific Northwest spruce tree came to have so many trunks.

A look into the Church of Scientology's deeply unfavorable view of psychiatry.

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

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

One of the dwarven trees dates back to 1625 and survived the Hiroshima bombing.

An acoustic anomaly with a mysterious cause.

This knobby, drooping New Orleans oak is a favorite place both for climbing and for meeting giraffes.

Florida might be at its most surreal in this museum devoted to the famed Spanish artist.

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

One of the world's oldest and most massive living organisms is a grove of quaking aspens.

The world's longest known cave system.

This geothermal hot spring hides beneath a slowly growing mineral dome.

Famously misunderstood wonder of the ancient world