As you can see from this picture, when you look down on the area from an airplane, there are a number of shapes, lines, and drawings clearly visible. A person standing on the grounds of the vast desert will see almost nothing. There is a tower to stand on which reveals parts of drawings, and gives an idea of how the lines extend.
The most interesting theory about the lines to this day is the one which believes they were a map for the use of ancient astronauts or pilots of India's vimana aircraft. Some feel that they were indicators of where to land in the desert, and others feel that the lines from the drawings pointed onwards to sacred sites where the astronaut was meant to land. (some lines do lead to significant sacred sites.)
Other schools of thought include those of Anthropology and Astronomy which believes the lines were painstakingly drawn by the locals of the area more than 2 thousand years ago to assist them in their agricultural pursuits.
