This 4,000-year-old historic site (105 Haverhill Rd., Salem, 603/893-8300, www.stonehengeusa.com , 9 a.m.–5 p.m. daily year-round, $9.50 adults, $8.50 seniors, $6.50 children 6–12, free children under 6) isn’t nearly as impressive as the giant stone tables of England’s Stonehenge, but the archaeological digs here have turned up some interesting and mysterious artifacts. Several stone structures on the site were most likely used by early Native Americans as dwelling places and a place for ritual animal sacrifices.
Exhibits explain how the site was laid out, like Stonehenge, as an accurate astronomical calendar. The site gets particularly crowded on the equinoxes and solstices, especially the Summer Solstice, which features a celebration each year. (Note: if you have Internet access, log on to the America’s Stonehenge website  for a dollar-off coupon on up to four tickets.)