This castle was built at the beginning of the 13C on the western bank of the Shannon. The rampart wall and its three fortified towers date from the late 13C. The oldest part is the central polygonal keep. At the beginning of the 19C, the upper level was considerably adapted in order to accomodate heavy artillery. From the battlements, there is a beautiful view overlooking the river. The Exhibition Centre and the museum retell the town's history.