Hyrule Castle was an ancient castle where King Harkinian lives. It's the capital of West Hyrule. Originally the castle was placed in Mushroom Kingdom and was named "Ludwig's Castle Hotel", but Mario and his pals invaded the castle and destroyed it with toasters.
Later Morshu bought the castle ruins and gave them to King as a present. King Harkinian built new castle in the center of Hyrule and named it "Hyrule Castle". But later it was moved west, because Squadala Man conquered East Hyrule.
Hyrule Castle was attacked by The Evil Forces of Ganon and was destroyed in 2009. Ganon set up them a bomb and the castle exploded. Spooky! Only Link died, but Zelda gave him Water of Life.
The King built a second castle from ruins of Hyrule Castle (which are ruins of Ludwig's Castle Hotel). In 2011, a group of highly trained monkeys destroyed the castle. The Hyrule Castle no longer exist. People say that King Harkinian was planning to create a new Hyrule Castle. A castle that is secured with sciencey stuff and gadgets.