Swansea Castle sits in the heart of this Welsh city, now surrounded by modern day buildings it's hard to imagine the castle's history. The castle was originally founded by Henry de Beaumont in 1106 but was rebuilt in the 13th Century, probably after being razed by the Welsh and now stands as ruins on a clifftop, below which the river Tawe originally flowed. The ruins of the castle make for a pleasant picnic spot on a sunny day.