A notable example of Norman fortified architecture. King John's Castle was built between 1200 and 1216 to guard Thomond Bridge, on the east bank of the River Shannon. It has no keep, but massive round towers reinforce its gate and the curtain walls, which used to be higher, for they were used to withstand the siege machines of the time. In 1216, the damage suffered during a siege was extensively repaired. After that, it was considered an important stromghold, as recorded in Irish annals and English State papers. In the 17C, a diamond-shaped cannon bastion was built by Josias Bodley (1611) and placed in the southeast corner. Likewise, the other towers and wall walks were lowered to accommodate cannon. Signs of the repairs done after the bombardment by General Ginkel in 1691 are still visible from Thomond Bridge. In the mid 18C, barracks (demolished) were built within the castle walls and parts of the eastern side of the fortifications were demolished to enlarge the parade ground. The history of the castle and city is retold in multimedia displays, including an audiovisual presentation, at the Visitor's Centre. This modern building has been raised to enable visitors to see the old Norman fortifications and three restored houses, discovered during recent excavations. In the courtyard, visitors can admire reproductions of war engines like the mangonel, the trebuchet and the battering ram.