King John's Castle was founded by King John in 1200AD not long after the Norman invasion in 1171AD. This castle is an imposing site with its five drum towers and tall curtain walls. It's situated on the banks of the Shannon River.
The castle houses a city exhibition, audio/visual show, a gift shop and heritage desk. There have been excavations on a site and nearby they have uncovered jewellery, pottery, weapons and even a small Viking village! The most historically significant find was a soldier's diary that recounts the horrors of the siege of the city.