Nahant: Tidepool and geology walks, marine research exhibits, touch tanks, tours, childrenâs activities, and a beach cleanup are part of the Northeastern Marine Science Center Open House. All ages are welcome. The center is ADA accessible. Saturday, 10 a.m.-3 p.m. Northeastern University Marine Science Center, 430 Nahant Rd. Free. 781-581-7370, www.northeastern.edu/marinescience.