The Duanesburg Historical Society will hold its Annual Picnic at 5 p.m. at Shafer Park, Chadwick Road Delanson. Bring your own place setting, a beverage and a dish to pass. RSVP to 895-2632 by Friday July 14 th . In case of rain, the picnic will be at Bishop Scully Hall, Delanson.

Discover Thacher Park's geology by observing limestone rock, sinkholes, and more!  Ages 16+. Registration encouraged. Call 518-872-0800. 9:30 a.m. Meet at the Thacher State Park Visitor Center (830 Thacher Park Road, Voorheesville NY 12186)

Northeast postal history and ephemera show. Saturday 10 a.m. to 6 p.m., Sunday 10 a.m. to 4 p.m. Polish Community Center (albanypcc.com) 2225 Washington Ave. Ext. Albany. Nphes.com

Community Caregivers’ lunchtime chat. Bastille Day: A day of celebrating in France. 1 p.m. All are welcome. Dial in to hear about interesting topics. (518)992-6661.

The Mystery of the Mary Celeste. Community Caregiver's Lunchtime Chat. 1 p.m. via free conference call at 518-992-66

Experiencing Ireland. Community Caregiver's Lunchtime Chat. 1 p.m. via free conference call at 518-992-66

Celebrating Erth Day. Community Caregiver's Lunchtime Chat. 1 p.m. via free conference call at 518-992-66

Rare Books Talk. Rare books dealer Eric Pederson will discuss the history of rare books, what makes a book rare (and what doesn't!), and answer any questions. Feel free to bring your books if there's anything you'd like Eric to take a look at. 7 p.m. at Rensselaerville Library 1459 County Route 351 Rensselaerville, 12147

Evening Hike. Join us as we search for American woodcock, spring peepers, drumming grouse, and other signs of spring renewal on this moderate 1.5-mile evening hike through forests and fields. Lanterns will be provided. Registration required. Call 518-872-0800. 7 p.m. at Thacher Nature Center, 87 Nature Center Way, Voorheesville 12186

Fly-In Breakfast. Fly-In Breakfast: “NY Air National Guard in the Vietnam War” 8:30 a.m. at Empire State Aerosciences Museum, 250 Rudy Chase Drive, Glenville, 12302