Odiham Castle, or King John’s castle as it’s locally known, is a medieval castle built by King John in the 13th century. One of only three fortresses built by the king during his reign, the ruins of the octagonal keep now stand alongside the much more recently constructed Basingstoke Canal.

The castle has an intriguing connection to the Magna Carta. It’s thought that it was from here that King John rode out to Runnymede in 1215 to attach his seal to the document.

But though King John signed the Magna Carta, he didn’t actually abide by the charter. As such, the First Barons’ War soon began, with King John and his forces battling French-supported rebels. As part of the conflict, in 1216, French knights besieged Odiham Castle.

The castle witnessed many other historical episodes. For centuries, it played host—and prison—to a range of royals, nobles, and once, even parliament. By the 14th century, the castle was used mainly as a hunting lodge rather than a fortress. By the early 1600s, it was essentially abandoned.

Now no more than a ruin, its huge walls still stand just shy of 30 feet tall and make for an impressive sight. There are a few information boards around and inside the keep, which give a brief history of the castle and explain parts of the construction.