"X" marks the spot of an echo chamber in the middle of a plaza.

An abandoned railroad tunnel forgotten by time awaits inquisitive hikers.

The statues commemorate the legendary mass killing of escaped circus monkeys.

The "last unrestored grand mansion of Savannah" is now a cramped, mouldering maze of antiques.

Suspended above the ground in a thicket of towering Georgia trees is a modern architectural wonder.

A white oak with property rights.

Where school buses go to die and be reborn as whimsical works of art.

The ruins of a cotton mill that was burned in the Civil War are still hidden in a Georgia forest.

One of the world's largest automobile junkyards is a unique landscape of metal and moss.

A curious whirlpool formation supposedly capable of entangling or engulfing branches, tree trunks, or whole rafts full of hapless tourists.

Constant erosion has created a surreal landscape of bleached and preserved fallen trees.

The perfectly named cave drop is the deepest in the continental United States, almost matching the height of Seattle’s Space Needle.

Just a few miles from downtown Atlanta is a trail covered in a crazy collection of outsider art.

A volcanic landmark located on an Ice age lake bed.

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

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

Curious cave that stays a cool 56 degrees all year long.

Bad farming practices caused this unnatural natural wonder.

This quiet park's strange sedimentary spires were named after Kodak's color film.

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

One of the world’s largest and deepest freshwater springs, where mastodons once roamed.

This Florida sinkhole hides a rainforest-like micro-environment in its depths.

The beauty and the beast of hydraulic mining is on full display at this California Historic State Park.

Even Henry David Thoreau found this glacial pothole irresistible.