The chakana (or Inca Cross) is a stepped cross made up of an equal-armed cross indicating the cardinal points of the compass and a superimposed square. The square is suggested to represent the other two levels of existence. The three levels of existence are Hana Pacha (the upper world inhabited by the superior gods), Kay Pacha, (the world of our everyday existence) and Ukhu or Urin Pacha (the underworld inhabited by spirits of the dead, the ancestors, their overlords and various deities having close contact to the Earth plane). The hole through the centre of the cross is the Axis by means of which the shaman transits the cosmic vault to the other levels. It is also said to represent Cusco, the center of the Incan empire, and the Southern Cross constellation.