Here’s where it all began—yes, here. The current site of the Echo Park Deep Pool is where Edward Doheny and his partner Charles Canfield drilled the first oil well in Los Angeles in 1892, using a sharpened eucalyptus tree. According to lore, they found the site after Doheny spotted a slick black substance on the wheel of a passing cart. As casually as possible, he asked the driver to show him exactly where he had come from.

Today, a plaque and adjoining park commemorate the first productive well drilled at Signal Hill. On June 23, 1921, a geyser of oil erupted from the Alamitos No. 1 well, leading to an explosion of drilling in the Long Beach area. By 1923, Signal Hill was the state’s largest field, and California was producing a quarter of the world’s supply of oil. Per the plaque, the monument is a “tribute to the petroleum pioneers for their success here, a success which has, by aiding in the growth and expansion of the petroleum industry, contributed so much to the welfare of mankind.” We’ll take their word for it.

Doheny may have set off the oil boom within the city of Los Angeles, but the first successful well in LA County was to the north, in the Santa Susana Mountains. A gusher at Charles Mentry’s Pico Well No. 4 on September 26, 1876, announced to the world that Southern California was rich in black gold. The nearby town of Newhall later became home to the state’s first refinery (pictured below).

Perhaps the most recognizable oil facility in the world, the Andeavor Refinery in Carson is adorned with an enormous American flag easily visible to drivers on the 405. Like Andeavor’s Wilmington refinery, this one dates back to the region’s oil boom of the 1920s and 1930s. Together, the two facilities now process a combined 380,000 barrels daily.

At the southeastern end of the Wilmington field is are the THUMS islands, constructed by the Texaco, Humble, Union, Mobil and Shell oil companies in 1965. As part of an agreement with the city of Long Beach, the oil companies invested considerable funds in disguising the drilling sites with boulders, palm trees, sculptures, and water falls—so much so that they are sometimes mistaken for luxury resorts.

Starting in the 1930s, Venice had a run as one of the leading oil producers in the state. During that time, derricks ran all along the canals and dotted the beach. Waterways became filled with oily sludge and the ocean was badly polluted. Production eventually dropped off in the 1970s and the last wells in the area were capped less than two decades later.

From the outside this edifice looks like a particularly soul crushing office building with no windows. Inside, however, it’s not a building at all. The structure is simply a shell disguising the site of an oil derrick slurping away at the Beverly Hills Oil Field.

One of the smaller major oil fields in the Los Angeles area, the Beverly Hills field is nonetheless productive, and the oil derrick on the campus of Beverly Hills High School was, until recently, churning out about 400 barrels of crude each day. The drilling site was ordered shut in 2016.

The Grove and Original Farmers Market today sit atop the Salt Lake Oil Field, discovered by dairy farmer Arthur Gilmore in the mid-1890s. Though the field was most productive in the early 20th Century, it was still being tapped in 1985, when drillers inadvertently caused methane gas to move below ground, rising up to the surface within the Ross store at Third Street and Fairfax Avenue. The resulting explosion injured 23 people.

It might not look like it, but this quiet residential street in Torrance was the site of the first major strike in the Del Amo oil field. Throughout the 1920s, this was one of the most productive fields in the LA area with nearly 1,500 wells spread across more than 3,500 acres.

Offshore oil rigs are a familiar sight to Huntington Beach residents and visitors. On and off land, drillers have been tapping the city’s oil field since the 1920s. Recent research from the U.S. Geological Survey suggests that it may, in fact, have been oil drilling here that triggered the Long Beach Earthquake in 1933.

Owned by the Archdiocese of Los Angeles, this two-acre oil facility in University Park was operated by a company called Allenco until 2013, when the firm suspended operations amid community complaints about health problems. Later, the Los Angeles city attorney hit the company with more than $1 million in fines and demanded it adhere to new regulations before reopening. Residents continue to demand a permanent shutdown of the site.