Mecca in Saudi Arabia is a very holy place in Islam -- whenever Muslims pray, they face Mecca. On our trip last year, there was an arrow in our hotel room in Cairo pointing towards Mecca (it was a circular wing, and it's hard to keep track of the direction). The Anti-Mecca is a place in the ocean exactly on the other side of the world from Mecca. Presumably, a group of Muslims there would face away from each other, since all directions face Mecca equally. We were only thirty kilometers away from this point on our cruise.