The National Trust have an Open Day at Penrhyn Castle about this time every year Hugo, I was going to go last year but something came up at the last minute. We got there about 11am yesterday and had a walk round the grounds and gardens first as the Castle wasn't open till 12 noon. When we entered the Castle we were lucky to have a long and informative chat with a very knowledgeable N.T. volunteer lady who told us all about the Pennant family and their connections with the Penrhyn Quarries in Bethesda, how the title of Lord Penrhyn was handed down through the family over the years and also how the building was used by the M.O.D. during the war. The slate staircase is unbelievably ornate and took years to construct and the kitchens, sculleries, ice tower etc are a revelation of life in the past "below stairs". It wasn't very crowded yesterday so we had plenty of time to have a good look round, it's certainly well worth a visit.