Though underground, the accelerator ring can easily be discerned from above because of a twenty-foot berm of earth on the ground above the ring. (Imagine a very skinny, four-mile-around bagel.) Many people assume the berm's purpose is to absorb radiation from the machine, but it's really there because [founding director Robert Rathbun] Wilson was an aesthetic sort of guy. After all the work of building the accelerator, he was disappointed that he couldn't tell where it was. So when the workmen dug out holes for cooling ponds around the accelerator, he had them pile up the dirt in this immense circle. To accent the circle, Wilson created a ten-foot-wide canal around it and installed circulating pumps that fire fountains of water into the air. The canal is functional as well as visual; it carries the cooling water for the accelerator. The whole thing is strangely beautiful. In satellite photos taken from three hundred miles above the earth, the berm-and-waterway—looking like a perfect circle from that height—is the sharpest feature on the northern Illinois landscape.