From PathfinderWiki

The great lighthouse of Hor-Aha is located on a small island north of the Coast of Graves in Osirion. During the height of ancient Osirion, the lighthouse was a key navigation aid. Its magical light not only marked the location but also gave information about the upcoming weather. Hor-Aha has remained dark for thousands of years, but recently lurid red and purple light strobes from its lantern room, the sign of violent gales. The few vessels that have since made landfall on the small isle were never heard from again.1


  1. Alex Greenshields, et al. “Land of the Pharaohs” in Osirion, Legacy of Pharaohs, 22. Paizo Inc., 2014