This is the Gryffindor Tower where the Gryffindor students reside here is their common room and Dormitories, it is one of the larger towers in hogwarts and one of the higher ones at that, it is well heated and illluminated.

The Owlery is a tower in Hogwarts Castle. Students' and school's owls are kept in the Owlery during the school year. Here you can get mail and send it, there are owl droppings around the floor and you can see many feathers/etc.

Astronomy is taught at night in the tallest tower of the School the Astronomy Tower. Astronomy is also the only field of study at Hogwarts which has a direct equivalent in the Muggle world. Known student activities include learning the names of stars, constellations and planets, as well as their location and movements, and describing the environments of planets and moons. Students need to get their own telescopes, but there are also telescopes in the tower, along with various models, items and such in the room. The room is a open roofed one.

The entrance is a ladder in the North Tower is the location of the Divination classroom at Hogwarts. It is filled with small fortune teller like tables, along with having crystal balls on them, there are many shelves with various things, along with strange things hanging from the ceiling, there are also many books, leaves, and plants. You can smell herbs and many other things in this room and it has a mystic feeling to it, or is it just the herbs and steam?