An earthwork sculpture built by Robert Smithson in the Great Salt Lake only reemerges during drought.

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

Two awe-inspiring globes from the reign of the Sun King hang from the ceiling of France's national library.

The old Niles Canyon Aqueduct in the San Francisco Bay Area is a bemusing and secret trail through nature for wayward travelers.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

A gigantic sculpture garden is packed with innovative oddities.

Double spiral staircases are not unheard of, but they are very rare.

An acoustic anomaly with a mysterious cause.

A huge musical instrument played by the ocean.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

On the Oregon coast there is a natural hole that seems to be draining the sea.

One of the largest ochre quarries in the world, hidden in a limestone landscape.

The most magnificent bottle house in a town strangely full of them.