Seville's cathedral was built over and incorporates a great mosque built by the Almohads in the 12th Century. So the architecture is a mix of Moorish and Christendom influence, really spectacular. The tower was built as a minaret in 1198, and the was changed over time to include the new belfry by 1568. The staircase inside was built so that the priest could ride his horse up to the top of the minaret.