Views of the Grounds. The Hogwarts Castle consists of an extensive school grounds surrounding it, which included sloping lawns, flowerbeds, vegetable patches, as well as a loch (called the Black Lake), a large dense forest (called the Forbidden Forest), several greenhouses and other outbuildings, and a full-size Quidditch Pitch. One of the castle's towers holds an owlery, which houses all the owls owned by the school and by students. The castle is set upon huge rocks above the Black Lake. Its three highest towers are the Astronomy, Ravenclaw, and Gryffindor Towers. The castle's 142 staircases are known to change position. The castle is known for it's many updates and changes in layout throughout the years. It should be noted that some rooms in the school tend to "move around," as do the steps on the Grand Staircase. Albus Dumbledore once noted that even he did not know all of Hogwarts' secrets. The castle had been around for centuries, and consequently has a long history of ancient magic. The school had numerous charms and spells on and around it that made it impossible for a Muggle to see it as the school; rather, they saw only ruins and several warnings of danger. Witches and wizards could not Apparate or Disapparate in Hogwarts grounds, except for when the Headmaster lifted the enchantment, whether only in certain areas or for the entire campus, so as to make the school less vulnerable when it served the headmaster to allow Apparition. Electricity and electronic devices are not found at Hogwarts. Due to the high levels of magic, Muggle substitutes for magic, such as computers, radar and electricity, "go haywire" around Hogwarts. Radios, however, were an exception as they were not powered by electricity, but by magic.