here’s a parking lot between Angel Stadium and California State Route 57. Most of the year it’s elevated on 7,000 cubic yards of soil, but between Christmas and New Year’s, workers from Dirt Wurx USA demolish the 45,000-square-foot expanse, mine the earth below, and dump it onto the Anaheim Angels playing field to build two supercross and five monster-truck courses. And once Feld Entertainment, the promoters behind Monster Energy Supercross and Monster Jam, are through with the venue, those same workers put it all back, right down to the field’s green grass and the lot’s white painted lines. They do this because dirt is worth exactly nothing until you need it moved. In California, it’s cheaper to build and destroy a parking lot each year than it is to store or haul the soil from elsewhere. It reduces the number of dump-truck meter hours, allows the crew to use larger-capacity off-road trucks, and eliminates the monthly expense of stockpiling dirt in a nearby leased lot, which Feld once did. Rich Winkler founded Dirt Wurx USA in 1992. He was a curious kid in the 1970s and excited about the process of making supercross tracks, especially because they took place in sporting cathedrals like the Los Angeles Coliseum where the playing field was considered sacred ground.