Even Henry David Thoreau found this glacial pothole irresistible.

This narrow canyon has been carved by the river over thousands of years into spectacular and curious forms.

The New England cabin where an infamous British occultist conducted experiments in "magick".

A 12,000-year-old bog boasting rare plants and fauna.

This giant Massachusetts sycamore is said to hold the dubious distinction of being the "widest tree East of the Mississippi!"

The walkable ruins of an 19th century hotel, destroyed in a horse cremation gone wrong.

A careful eye can find hundreds of dinosaur tracks running along the Connecticut River.

San Francisco Bay's ghost town.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

A grove of "candelabra redwoods" deep in California's Lost Coast.

A trash dump made beautiful by nature's power.

A raised boardwalk winds through a thicket of stunted, century-old trees no more than nine feet tall.

The mysterious round rocks of Schooner Gulch.

Massive prehistoric mammals used these stones as oversized scratching posts.

An abandoned, unfinished mansion on grounds strewn with lava rocks.

Law-protected wreckage serves as a peculiar memorial for an almost forgotten World War II tragedy.

Across Ring Mountain is a vast collection of Native American petroglyphs unique to the region.

The fossilized remains of ancient California redwoods.

Here, visitors can swing with the waves of the Pacific Ocean.

These millipedes glow not out of attraction, but as a not-too-subtle warning.

A volcanic tunnel illuminated by natural skylights offers a shaded respite from the desert sun.

One of the last free public hot springs is decorated with hippie art.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

This massive redwood tree has a hole in the base big enough to drive through.