Wentworth Woodhouse near Rotherham, South Yorkshire. The east front is 185m long and is the longest country house facade in Europe. The house has 365 rooms (one for every day of the year perhaps) and covers an area of over 2.5 acres. It is set in 150 acre's of parkland (a very nice walk down to Greasbrough) and was the inherited family seat of the Earls Fitzwilliam.