Though Earth Day is synonymous with protecting the environment, the holiday can trace its roots to an environmental disaster that occurred in Southern California in 1969. Over a 10-day period that began on January 28, 1969 just six miles off the coast of Santa Barbara, Calif., roughly 80,000 to 100,000 barrels of crude oil spilled into the Santa Barbara Channel and onto the beaches of Santa Barbara County. Thousands of birds and marine animals, including dolphins, elephant seals and sea lions, were killed as a result of the spill, which at the time was the largest such spill to ever occur in United States waters (it is now the third-largest spill after the Deepwater Horizon spill in 2010 and the 1989 Exxon Valdez spill). Though devastating, the Santa Barbara oil spill proved inspiring to Senator Gaylord Nelson of Wisconsin, who is today considered the founder of Earth Day. Senator Nelson used the sense of social consciousness that prevailed throughout much of the United States in 1969 and the outrage at the Santa Barbara oil spill to infuse energy into a growing movement to raise awareness about air and water pollution. His risk paid off, as more than 20 million Americans took to the streets on April, 22, 1970 to demonstrate for a healthy, sustainable environment.