Castles are medieval buildings which were defensive homes for powerful people . They could be made from wood, stone, or brick , and some were used for hundreds of years. Thousands of castles were built across Europe, the Middle East, and Japan with different designs. Today, most castles are ruins and many are popular tourist attractions. In England and Wales castles were first used by the invading Normans led by Duke William in 1066. They provided a base for lord of the castle to control the surro