Castles originated in the Middle Ages, primarily in Europe, as fortified structures for defense and residence. They were built by nobles and kings to protect their lands from invaders and to assert their power. The design of castles evolved over time, with features like thick walls, moats, and towers becoming common to enhance security. By the late Middle Ages, castles began to lose their military significance due to advancements in warfare, such as cannons. Many were transformed into luxurious homes or abandoned. Today, castles like Neuschwanstein in Germany and Edinburgh Castle in Scotland serve as historical landmarks and tourist attractions.