Located on a small hill on the south bank of the Thames and built by William I, Windsor Castle was designed to protect ships and the royal family on the Thames. Windsor Castle is divided into the Upper Ward, Middle Ward and Lower Ward. The Upper Ward comprises rooms such as the 13th-century Queen's Ballroom and the banquet hall where the British Royal Family holds major activities. The Round Tower is in the Middle Ward surrounded by a rose garden, where the royal family's documents and collected photographs are preserved. St. George's Chapel in the Lower Ward is luxurious Gothic architecture and a classic building in Windsor Castle.