Or it's a conference center.
This is Leeds Castle, which is nowhere near the town of Leeds. It's near Maidstone, Kent, halfway between #London and Folkstone on the way to Dover.
I've visited there twice, in 2004 and 2005. Different seasons. In spite of the cloudy weather, this was early July 2005. Tuesday the 5th or Wednesday the 6th; I don't remember exactly. I lost a day on the trip to Stonehenge. Didn't even get pictures.