The landfill opened in 1948 as a temporary landfill, but by 1955 it became the largest landfill in the world, and it remained so until its closure in 2001. At the peak of its operation, in 1986, Fresh Kills received 29,000 tons of residential waste per day, playing a key part in the New York City waste management system. From 1991 until its closing it was the only landfill to accept New York City's residential waste. It consists of four mounds which range in height from and hold about 150 million tons of solid waste. The archaeologist Martin Jones characterizes it as "among the largest man-made structures in the history of the world."