TONGA: A detailed study of 196 stone tools shows that the chiefdom that arose in the archipelago around 800 years ago was the center of a trade network that spanned Oceania. Two-thirds of the tools analyzed came from rock sources on other island groups, including Samoa, Fiji, and the Society Islands, some 1,500 miles away. Between A.D.1300 and 1500, cultures around the Pacific began to build monumental structures and see an increase in chiefly power. The Tongan trade network might explain how such traditions moved across such vast distances.—SAMIR S. PATEL