In the scene where the ark is taken by the Nazis, you can see in the background that there is an island or strip of land in the distance. There are even green shrubs. Yet after Indy is on the sub and the map is brought up, you can clearly see that they are in the middle of the Mediterranean. The land is too close to be any of the land masses on the map.

The best example of the land is 1:34:44 and the map is 1:38:02