Four small, suspiciously round islands dot the harbor of Long Beach, California, visible from the shoreline or as you descend into Long Beach Airport. They are ringed by palm trees and blue-and-white towers reminiscent of high-rise condos on the mainland. But these islands aren’t quite what they seem.

These manmade isles, dubbed the Astronaut Islands, are the only decorated oil islands in the U.S. Measuring 10 acres each, they were built in 1965 as part of a city beautification project to camouflage offshore oil derricks and muffle their sound.

Construction of the islands was overseen by Disneyland architect Joseph Linesch. To disguise the industrial oil production, he planned waterfalls, screens, and extensive landscaping along with the condo-style camouflage, and colorful lights at night. The islands are ringed by rocks from Catalina Island and filled with millions of cubic yards of material dredged from the bay. The result is, as a Los Angeles Times reporter put it, “part Disney, part Jetsons, part Swiss Family Robinson.”

The islands were originally known as the THUMS Islands, based on the name of the oil consortium that built them: Texaco, Humble (now Exxon), Union Oil, Mobil and Shell. Since 1967, they have been commonly referred to as the Astronaut Islands, with the islands named after the American astronauts killed in an accident in preparation for the Apollo 1 mission.  

Workers still commute there via barge to wrest 46,000 barrels of oil from the earth each day, but as for visitors, the islands are off-limits with the exception of occasional guided tours hosted by private organizations.