Learn about the Middlesex Canal, the greatest work of its kind in the United States until the Erie Canal. Kayakers can take out above the Billerica Falls Dam at the canal entrance/parking lot at 2 Old Elm St. and walk part of the canal that Henry Thoreau traveled between the Merrimack and Concord Rivers. For children, a Lego® canal playground, a watered model lock and a scavenger hunt. Find the pigeon, squeezable beaver, muskrat and three mice. Free, Middlesex Canal Museum, 71 Faulkner St.

Possibly the oldest inland monument in Massachusetts, the Two Brothers Rock are well known but difficult to find. Former Bedford Historical Society president Alethea Yates will lead a 15-minute walk to these two large boulders on the shore of the Concord River and then tell the story of the 1638 trip of the original “two brothers” — to this historic site. Mosquito repellent recommended. Meet at the trailhead on Dudley Rd, Bedford, near the intersection of Emery Rd.

A sunrise paddle along the Concord River through the Carlisle, Bedford and Billerica sections of Great Meadows National Wildlife Refuge, with a stop for a hearty breakfast at a casual riverside restaurant. Bring your own canoe or kayak and life jacket (required), appropriate clothing for a 2–3 hour paddle, binoculars if you have them, and drinking water. Meet at 5:15 AM at the Bedford Boat Landing (Rt. 225).

Naturalist Peter Alden, author of the Audubon Field Guide to New England, will lead an easy 2.5-hour walk focusing on birds and plants on the Bruce Freeman Rail Trail from West Concord toward White Pond. Meet at the beginning of the Rail Trail in West Concord (Rt. 62).