Oxford's Bodleian Library is one of the oldest public libraries in the world and quite possibly the most impressive one you'll ever see. Visitors are welcome to wander around the central quad and the foyer exhibition space. For £1 you can visit the Divinity School, but the rest of the complex is only accessible on guided tours. Check timings online or at the information desk. Advance tickets are only available for extended tours; others must be purchased on the day.

The Bodleian has its roots in a 15th-century collection of books and its present state is largely due to the efforts of Sir Thomas Bodley, a 16th-century fellow of Merton College. He founded the library in 1602 and, in 1610, came to the agreement with the Stationers' Company of London that it would receive a copy of every single book published in the UK – an agreement that still stands today. The library started off with 20 books; it currently holds more than 12 million items, contains 117 miles of shelving and has seating space for up to 2500 readers. A staggering 5000 books and articles arrive every Wednesday, all of which need to be catalogued and stored.

The oldest part of the library surrounds the Jacobean Gothic Old Schools Quadrangle, which dates from the early 17th century and sports some of Oxford's odder architectural gems. On the eastern side of the quad is the Tower of Five Orders, an ornate building depicting the five classical orders of architecture. On the western side is the exquisite Divinity School, the university's first teaching room. Completed in 1488, it is renowned as a masterpiece of 15th-century English Gothic architecture and has a superb fan-vaulted ceiling sporting the initials of its many benefactors. It featured as the Hogwarts hospital wing in the Harry Potter films.

Half-hour mini tours (£6) include the Divinity School and the medieval Duke Humfrey’s library, where no fewer than five kings, 40 Nobel Prize winners, 26 British prime ministers, and writers such as Oscar Wilde, CS Lewis and JRR Tolkien studied amid rows filled with grand ancient tomes chained to the shelves. It also featured in the Harry Potter films as Hogwarts library. Those wishing to read here (books may not be borrowed) still have to swear Bodley’s Oath, which involves vowing not to bring fire or flames into the library.

Hour-long standard tours (£8) also visit the 17th-century oak-panelled Convocation House, where parliament was held during the Civil War, and the Chancellor’s Court, in which Oscar Wilde and Romantic poet Percy Bysshe Shelley were tried (for debt and promoting atheism, respectively). Extended 1½-hour tours (£14; 9.15am Wednesday and Saturday) include the Radcliffe Camera, the Upper Reading Room and the underground Gladstone Link. Otherwise, pick up a 40-minute audioguide (£2.50).

Some of the library's collections are now housed in the newly renovated Weston Library (Broad St), which opened to visitors in 2015.