Hogwarts. The world's premier school of witchcraft and wizardry

Hogwarts is a castle, with towering towers, ancient stone walls, suits of armour, tapestries and all the other trappings of an ancestral pile. Having been an institute of magical education for over a millenium, the castle is seething with magic of its own, from the Grand Staircase whose stairs shift around constantly to the Room of Requirement, which only appears when you need it to, and equips itself with whatever you need. A giant squid swims in the lake, along with Mermen and numerous water sprites and demons such as Grindylows. All manner of magical creatures live in the Forbidden Forest, Centaurs, Unicorns and giant spiders to name a few.