The Million Barrel is a concrete-lined oval some thirty feet deep and over five hundred feet in diameter that was built as an oil storage tank in 1928 by Shell Oil. At the time, oil was being pumped from the ground faster than it could be shipped out by train, and Shell needed a place to store it. The tank, designed to hold up to a million barrels, was lined with concrete panels separated by rubber gaskets, and it originally had a wooden roof to slow evaporation. As the historical marker at the site says, “It was filled to capacity only once.” The gaskets failed, and vast quantities of oil leaked into the ground. Since 1986, the tank has held a covered band shell and stage, constructed of dark-stained wood, on its eastern lip; concertgoers park in the tank.
Added to the site in the 1980s were a Texas and Pacific Railway section house, the old Monahans jail, a Million Barrel Museum, and the Holman House, the boyhood home of Eugene Holman, a petroleum geologist and president of Standard Oil of New Jersey from 1944 to 1960.