My wife recently constructed a beautiful labyrinth in our garden.  Labyrinths have been around for thousands of years and are found in almost all religious traditions as well as cultures including Native American, Greek, Celtic and Mayan.  Like Stonehenge and the pyramids, they are magical geometric forms that define sacred space.  When one walks a labyrinth, he meanders back and forth, turning 180 degrees each time he enters a new circuit.  Changes in direction induce shifts in states of awareness.