arvard’s oldest fossils aren’t the ones teaching classes, but the cool collection of 12,000 specimens in the university’s natural history museum. The museum houses three of the university’s centuries-old institutions—the Mineralogical and Geological Museum, the Harvard University Herbaria and the Museum of Comparative Zoology—and exhibits a diverse display of rare and abnormal artifacts in a cool, old-fashioned space with hanging whales, giant dinosaur skeletons, even meteorites. The highlight is the world-renowned collection of 3,000 glass flowers created by a father-and-son team from Germany in the late 1800s to be used in Harvard botany classes. Also be sure to check out the world’s most complete kronosaurus, and the “Harvard Mastadon.” Thought you already knew this? Okay, here's the secret: Admission is always free to Massachusetts residents Sunday mornings from 9 a.m. to noon and Wednesdays from 3 to 5 p.m. during the school year. Rineman