The most-visited of Harvard’s attractions, the museum has dinosaurs—including a Triceratops skull the size of a Smart car and a 42-foot-long prehistoric marine reptile—plus a spectacular Great Mammal Hall with land creatures behind glass at floor level and giant whale skeletons overhead. There’s a splashy room of incredible sparkling gemstones, including a 1,600-pound amethyst geode from Brazil. Also here are the world-famous Blaschka Glass Flowers, 4,300 vividly realistic models of flowers, leaves, and other plants created by the father-and-son team Leopold and Rudolf Blaschka, from Dresden, Germany. (The gallery that houses many of the glass models was given an extensive renovation in 2016; many of the items nearly glow now.) The museum is just the right size for families with curious children, and a small gift shop has a smart collection of educational items. Note that the galleries are on the building’s third floor (up 51 steps) and that the main entrance is not wheelchair-accessible. The North Entrance, on the left side of the building, is fully accessible and has an elevator.