Joshua's Hill rises above the Asian side of the Bosphorus near Beykoz and is traditionally associated with the tomb of the biblical Joshua. The hill is one of the steepest points close to the strait, so the appeal is as much the climb and the view as the shrine itself.
Come on a clear day if you are exploring the northern Bosphorus. It works best as a short stop combined with other sights along the water rather than as a trip across the city on its own.