If your mansion sits on more than nine acres, you have to do something with all that space. Why not construct an enormous athletic complex and consign the leftover land to "incredible landscaping"? Why not build such an elaborate estate that the Corcoran listing just throws up its hands and says the amenities are "too many more to mention"?

Why not? Because it costs $49.5 million. But hey! If that sounds like chump change to you, keep reading.

With that kind of cash on the line, the property has to have a history dating back at least to 1915—which, luckily, this one does. Having been "lovingly restored," the 18,000-square-foot palace features "intimate elegant rooms, many with fireplaces." But the real treats are outside: The yard includes "rose gardens," "flowering shrubs," "evergreen perimeters" and, our favorite, "old trees." The other amenities are "resort-like": two pools (one indoor, one outdoor), a tennis court, a paddle court, a carriage house, a four-car garage and, oh yes, a gymnasium. The listing says "no expense was spared," and we finally understand what that means.