For much of the middle ages, Pisa's powerful navy ensured its dominance of the western Mediterranean. Trading links with Spain and North Africa in the 12th century brought vast mercantile wealth and formed the basis of a scientific and cultural revolution that is still reflected in Pisa's splendid buildings-espcially in Duomo, Baptistry and Campanile(Leaning Tower). Pisa's decline began in 1284, with its defeat by Genoa, and was hastened by the silting up of the harbour. The city fell to the Florentines in 1406, but suffered its worst crisis in 1944 when it fell victim to Allied bombing.