More than just a fantasy structure, Belvedere Castle maintains a real belvedere – architectural lingo for “observatory” or “tower.” Part Roman temple, part Goth castle, and part Greek edifice, this Central Park landmark was once only a fake front with open windows and doors overlooking Turtle Pond, the Great Lawn, and one of the famous park’s original reservoirs. Now a total building, the Belvedere is home to the Henry Luce Nature Observatory, where naturalists give off-the-cuff lessons using telescopes, microscopes, feathers, and even skeletons.

Mid-Park, at 79th St.