We’ll have a short, brisk walk, looking at a landmarked Upper East Side 19th-century public school that preserves traces of an open-air classroom, a public-health initiative from the days when TB was our number-one cause of death, and end at noon at one of last high schools designed by Charles B. J. Snyder to enjoy a Metropolitan Opera Simulcast of Handel’s Giulio Cesare. Bring lunch /water. Call or email for the meeting place the week of the hike. Leader: Jean Arrington 646-290-4119 or Jean.email@example.com . Nonmembers: $3.