Castles may have been reserved for the noble and elite centuries ago, but now many of the striking structures have transformed into luxury hotels for romantic rendezvous or memorable family getaways. The fortified buildings -- with buttresses, stone arches, and ornate detail -- no longer protect against attacks, instead offering travelers a historic and undeniably unique place to stay. From Ireland to Tuscany, we've rounded up the best castle hotels in Europe when you want to sleep in a bed that's fit for a queen or king.