Light still pours into the ruins of this ancient Islamic observatory.

A dormant lightning machine equal to all the power in Russia.

Ukrainian defense contractor's center for studying "pyramid energy."

A large instrument played by the wind.

A burnt orange monolithic dome structure perched on a hillside near Interstate 280.

If you are looking for a used Russian battery, Chinese Ham Radio or other electronic oddities this Flea Market is a good place to start.

From the Difference Engine to the Cray-1, all under one roof.

A 90-acre park on former landfill that hosts an annual kite festival.

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

A hidden subterranean installation offers a view of the sky.

Art in the form of a winding, man made crack in stone.

A huge musical instrument played by the ocean.

A modern mechanical planetary system, part of a 10,000 year clock.

A collection of 20th-century automata, penny arcade games, and musical contraptions.