The Innocents Abroad by Mark Twain

We whisked by many a gray old medieval castle, clad thick with ivy that swung its green banners down from towers and turrets where once some old Crusader's flag had floated. The driver pointed to one of these ancient fortresses, and said, (I translate): "Do you see that great iron hook that projects from the wall just under the highest window in the ruined tower?" We said we could not see it at such a distance, but had no doubt it was there. "Well," he said; "there is a legend connected with that iron hook. Nearly seven hundred years ago, that castle was the property of the noble Count Luigi Gennaro Guido Alphonso di Genova----"

Oxburgh Hall, Norfolk

Notre-Dame de Paris by Victor Hugo

The Abbey of Saint-German-des-Pres was castellated like a baronial mansion, and more brass expended about it in bombards than in bells.

Boughton House, Northamptonshire

The Road to Oz by L. Frank Baum

It would be hard to match this castle in Kansas; wouldn't it, little Dorothy?

Hardwick Hall, Derbyshire