Dublin Castle (1)

Dublin Castle is situated in the historic part of the city. By 930's it was a Danish Viking fortress and in 1204 was fortified at King John of England's order.
The castle itself it's not very spectacular, but it's interesting to visit .
Nowadays it has conference and tourist facilities; so, if you have an event to prepare, this could be a suitable location.

More about the castle on www.dublincastle.ie.