Shoreline Amphitheater in Mountain View, California was built on a garbage landfill. Hilariously, during some of the first concerts there, at that moment when everyone raises a lighter at the start of their favorite bands set... there were some ignitions of the methane leaking from the landfill. So they had to go back and do an expensive retrofit of an massive pipe network under the (outdoor) amphitheater to vent the methane to someplace safe. Yeah, that's the same place I was ushering a Grateful Dead concert, demanded to see Bill Grahms's ticket because i didn't recognize him, and he just said "I work here" and brushed right past me. (He didn't carry a pass, he just expected everyone to recognize him.)