Driving down Ocean Boulevard, you might have noticed four strange-looking islands just offshore. These islands are adorned with palm trees and white and blue towers. They are oil derricks, but thanks to a city project in 1965, the islands camouflage themselves as part of the aesthetic landscape of Long Beach.

Joseph Linesch, who designed Disneyland, among other theme parks, oversaw the construction of the islands—known then as the “THUMS” Islands. They were named for the oil coalition that had the islands built, Texaco, Humble, Union Oil, Mobil, and Shell. It seems fitting that Linesch was chosen as the architect of the islands, given his amusement park background, because the islands, at 10-acres each, are the only well-decorated oil islands in the United States. It’s all a facade, however. Among all those palm trees, large buildings, and lights that shine brightly at night, something extraordinary is taking place.

The islands produce about 40,000 barrels of oil each day through underwater reservoirs that channel oil and natural gas. These reservoirs are located about a mile under the harbor. A pipeline transfers this oil and natural gas to shore where it is sold. Since 1967, the islands have also been known as the “Astronaut Islands,” which is fitting, given Long Beach’s history in the aerospace industry. Island Grissom, Island White, Island Chaffee and Island Freeman are all named after four United States astronauts killed on a mission.

The islands are built into the fabric of Long Beach. And now, driving down Ocean Boulevard, or peering off the bluff, you might take even more notice of the islands—now that you know that there is a lot more going on there than meets the eye.