Los Angeles is known as LA LA Land. It's home to Hollywood, Beverly Hills, palm trees and fabulous attractions. And it's also the base for an enormous oil operation. You'd never know it, but there are oil rigs hidden inside buildings all over the city of Los Angeles. This is the industrial black heart of one of America's most famously beautiful cities.

Early Discovery No one bothered to hide the oil rigs in the 1890s, when the oil fields were first discovered in the LA. Almost one-quarter of the world's oil was produced in California by the 1930s. Rigs were encased in soundproof walls and equipment was hidden away as people began to pour into LA. They didn't want to live next to oil rigs -- at least, not where they could see them. This is what Venice Beach looked like in 1952. It doesn't look like this today.

LA Oil Fields The LA oil fields are among the country's most productive. The rigging is hidden among the flashy boutiques, the million-dollar homes and the acres of green golf courses that make LA a gleaming jewel of the west coast. There are about 55 active oil fields here and more than 3,000 oil derricks pumping away from positions all over the city.

Hidden Among Us LA is the third-largest oil field in the U.S., and there is rigging literally everywhere. One oil derrick is installed right on the grounds of Beverly Hills High School, and it’s not even hidden all that well.

The Fake City Others are hidden in faux buildings, like this one. The soundproofed walls have no windows. The entire building is meant only to cover a derrick that roams around inside. It's built on a track to pump oil from 50 different wells.