Celebrate #WorldHeritageDay by learning more about the international sites and monuments recognized by UNESCO around the world. _ The prehistoric monuments at #Stonehenge, England, and nearby Avebury, are some of the earliest known man-made monuments. The 6,500-acre site offers walking tours and has volunteers on site to answer questions, as well as exhibits and replicas of neolithic homes. World Heritage site since 1986. | 📷: David Goddard | November 1, 2006 | #TravelTuesday [1 of 5]