This is the Fatima az-Zahra Mosque but is called “The Floating Mosque” because at high tide, the mosque appears to be floating in the Red Sea. I had read about it on TripAdvisor, which at the time was the only place I could find any information about what to see in Jeddah (even Lonely Planet was written from Internet research due to problems with journalists entering the country and so had basically nothing). I described this mosque to our driver, and he knew immediately where it was. He said it was a favorite place for pilgrims on umrah (the lesser Hajj) from Malaysia and Indonesia to congregate, and sure enough, they were there in large numbers.