The Hartford-born William Gillette (1853-1937) was a successful actor and playwright known primarily for his portrayals of Sherlock Holmes. He took his money and ran to this hill rearing above the Connecticut River, where he built a 24-room mansion. It's difficult to believe, though, that he really thought the result resembled the medieval fortresses that allegedly were his inspiration: Rock gardens by roadside eccentrics in South Dakota are closer relations. The all-stone exterior has the dripping look of a sandcastle built by wet globs that fell through children's fingers; inside, Gillette designed oddities such as a dining-room table that slid into the wall, an inexplicable space-saving effort.

But no one can argue with his choice of location. The mansion sits atop a hill above the east bank of the Connecticut River, with superlative vistas upriver and down. Nowhere else is the blessed underdevelopment of the estuary more apparent. The expansive grounds, which are now owned and managed by the state, have picnic areas and nature trails. Because the home's terrace can be entered for free, many visitors come just to take in those views.