The prehistoric alignment of world wonders : The Great circle Great circles are straight lines that go all the way around the centre of the earth. The equator is a great circle. Meridians of longitude that cross over the north and south poles are also great circles. For every location on a great circle, Easter Island, Nazca, Ollantaytambo, Paratoari, Tassili nAjjer and Giza are all aligned on a single great circle. Additional ancient sites that are located within one tenth of one degree of this great circle include Petra ; Perseopolis ; Khajuraho ; Pyay, Sukothai and Anatom Island. Near Ollantaytambo, Machupicchu and Cuzco are within one quarter of a degree. The Oracle at Siwa in the western Egyptian desert is within one quarter of a degree. In the Indus Valley, Mohenjo Daro and Ganweriwala are within one quarter of a degree. The ancient Sumerian city of Ur and Angkor temples in Cambodia and Thailand are within one degree of the great circle. The Angkor temple at Preah Vihear is within one quarter of a degree.