Get out that map of the Freedom Trail and pick your starting point — the trail is not a loop so it’s best to start at one end or the other. Most people start at Boston Common and make their way along the 2.5-mile red brick path to visit some 16 of Boston’s most important sites. Allow a minimum of three hours to walk the trail and stop in at some of the attractions like the Paul Revere House and the U.S.S. Constitution. When the trail winds its way through the North End, divert off the path for lunch at Pizzeria Regina and sample Boston’s most popular pizza steaming hot and fresh from the brick oven.