Discover Dogtown Nature Walk. Dogtown Common. Gloucester. 2:30 p.m. to 4:30 p.m. Join Jane Winchell, The Sarah Fraser Robbins Director of the Art & Nature Center, and explore the ghost town's local legends and natural wonders, including a series of large boulders inscribed with messages carved during the Great Depression. Reservations by Oct. 16. Members $8 (children age 16 and under $6); nonmembers $10 (children $8). 978-745- 9500. www.pem.org.