Zeitgeist

The world of Zeitgeist has three unique magical traits due to the nature of the planes it draws energy from. First, 200 years ago the connection to the plane of air was damaged, so now no spell or magic item can allow for permanent flight. PCs can still have flight magic of their own, but no effect ever lasts longer than five minutes, and people still react to flying mages with amazement because of how rare the magic is.

Second, gold blocks teleportation. Line of sight for short-range teleportation cannot pass through any door or window that has even a thin wire of gold tracing its frame, and a creature wearing a ring of gold cannot teleport. Third, the Axis Seal inhibits planar travel. Unless the caster has a rare and special connection to another plane, magic cannot allow a creature to travel to another plane permanently, and even powerful effects will end abruptly after five minutes.