In "Vladimir Nabokov: A Pictorial Biography" by
Ardis Publishers,1991 (published in Brazil in 1994) we can see the
reproduction of a photograph showing a mansion in Abbazia (Villa Neptune).
The caption beneath mentions that it was visited
by Nabokov when he was 5 years old and felt homesick for Vira for the first
time.
I wonder if this crenelated mansion in any way
served as inspiration for VN's "Cloud, Castle, Lake" short-story. It certainly
wouldn't be representative of any kind of "timeless
happiness"!