World of Omphalos
Omphalos is covered by a web of Ley Lines.
Ley lines are pathways of energy that cris-cross the world. Usually they are invisible, but in darkness and in the light of the moon, they glow faintly becoming visible to the naked eye.
A Place where ley Lines cross each other is called a ley nexus. Some nexus are simply intersections of two different Ley Lines, however some have been found with intersections of a dozen different ley lines.
See House Rules for the effects of standing in a Ley Line or Ley Nexus.