 Covering a space approximately one and a quarter miles long and more than a quarter of a mile wide (2 km by 0.4 km, roughly the scale of the National Mall), "City" is one of the largest sculptures ever created.Using earth, rocks, sand and concrete as building materials and assembled with heavy machinery, the work comprises five phases, each consisting of a number of structures referred to as complexes, with some of the structures reaching a height of eighty feet.