MAINE - Augusta/Kennebec

Built in 1754, this National Historic Landmark is America's oldest surviving wooden fort. Visitors can tour the fort and its store, which contains hundreds of farming and forestry tools essential to the economic life of the settlement. Open 1 to 4 p.m., Memorial Day to Labor Day, and weekends or Sundays only Labor Day through January.

This 224-acre arboretum has a five-mile, year-round trail system for hiking, jogging, bird watching, bicycling, horseback riding, and cross-country skiing on groomed winter trails. Visitors can have a picnic, take photos, look for birds. Pets are permitted on a leash. Trail maps available. Open daily, dawn to dusk.