Gibralter land bridge?

How come there isn't a land bridge in gibralter like sicily?

Because we analyzed the distances across most of the straits on our map and then also took somewhat into consideration the ease of crossing and historical frequency of crossings and used those factors to make our final decision. Also RTW engine issues had to be considered, like how in 1.5 getting the AI to attack islands or cross from an island to the mainland is really difficult.