One of the most beautiful Castles in Portugal is only a few miles away from Fatima. This is the only one of all the Portuguese castles that is built on the central stretch of a river. The origins of the Castle of Almourol are unknown and enigmatic. Some defend that it was built by the pre-Romans, while others defend that it were the Lusitanian. One thing is certain, the project instigators made the Tagus River even more beautiful by devising the Castle of Almourol on that small island.