One of the world’s longest pedestrian suspension bridges.

A sculpture made of 10 Cadillacs as a monument to the "Golden Age" of the American automobile.

Giant heads occasionally litter the industrial Houston neighborhood where sculptor David Adickes has his studio.

Tucked away down this Baytown alley exists a one-of-a-kind art exhibit of technicolor umbrellas.

An exercise in patience and imagination, where Mother Earth turned common stuff into precious hidden treasures.

Mysterious ancient petroglyphs carved on a glacial boulder at the tip of Bainbridge Island.

This large Sitka spruce that appears to be floating in mid-air, has defied logic for years.

Native American burial mounds? Giant gopher dens? No one knows what created the Mima Mounds.

The story behind the mysterious symbol painted in front of the historic university's famous Rotunda.

A double agent hid information for the Soviet Union beneath this bridge for more than 20 years.

An architect's childhood fantasy treehouse made real.

The crumbling structure is a rare surviving relic of the area's bygone mining industry.

This abandoned train tunnel has been the subject of countless ghost stories for years.

The highest peak in the state of Vermont has some interesting features.

A gardener's enduring labor of love is spread throughout a small Vermont town.

The world’s largest underground marble quarry is hiding in Vermont.

Tour the world's largest deep-hole dimension granite quarry, where you can view the plant where gravestones are made and roll a ball down the outdoor granite bowling alley.

This cavernous abandoned marble mine is popular with ice skaters in the winter.

This overlooked gem outside Niagara Falls preserves and celebrates Iroquois culture.

A technicolor place of worship for Elevationists.

This abandoned mine offers a glimpse at what life was like for those who came to Alaska seeking Gold Rush riches.

A unique flight of canal locks that owe their form to 19th-century cost-saving measures.

A former utopian healing center created by a huckster and built by derelicts.

No one's quite sure why there's a metal megaphone bolted on two rocks in the middle of the Mojave Desert.