This stone castle is overlooking the Connecticut River. It looks like a classic fortress, but the interior is quite different. Ordered and partially designed by William Hooker Gillette, who played Sherlock Holmes onstage, the 24-room castle included strange features – original doorknobs and locks, hidden surveillance mirrors, and about 60 images that pay tribute to his 17 cats. No two doors are the same in this castle. Gillette's own walking paths were constructed with near-vertical steps, stone-arch bridges, and wooded trestles.