genes, and the hybrid Polynesian breadfruit. The period 900 to 1700 CE of the Marianas, immediately before and during the Spanish colonization, is known as the Latte period. It is characterized by rapid cultural change, most notably by the massive megalithic latte stones (also spelled latde or latti). These were composed of the haligi pillars capped with another stone called tasa (which prevented rodents from climbing the posts). These served as supports for the rest of the structure which was made of wood. Remains of structures made with similar wooden posts have also been found. Human graves have also been found in front of latte structures, The Latte period was also characterized by the introduction of rice agriculture, which is unique in the pre-contact Pacific Islands. The reasons for these changes is still unclear, but it is believed that it may have resulted from a third wave of migrants from Island Southeast Asia. Comparisons with other architectural traditions makes it likely that this third migration wave were again from the Philippines, or from eastern Indonesia (either Sulawesi or Sumba), all of which have a tradition of raised buildings with capstones. Interestingly, the word haligi ("pillar") is also used in various languages throughout the Philippines; while the Chamorro word guma ("house") closely resembles the Sumba word uma. Spanish exploration and control The first Europeans to see the island group were a Spanish expedition, who on March 6, 1521, observed a string of islands and sailed between two of them during a Spanish expedition of world circumnavigation under the command of Ferdinand Magellan. Historically, the southern village of Umatac, Guam has been credited as the site of the Spanish landing. As confirmation, a scholarly study of the navigator's diary, now kept in preservation in the Philippines, revealed a drawing of the islands with a tiny island to the south of a much larger island above it. The described placement of the islands confirms that Magellan had actually sailed between Guam and Cocos Island, and not Guam and Rota, as some originally thought. Especially since the Northern areas of Guam do not have safe coves or harbors to anchor. Moreover, the waters of Northern Guam are oftentimes more rough and the currents are even more treacherous in comparison to the safer coves and currents seen throughout South-Western side of Guam. Regardless of where they landed, Spanish ships arrived in Guam and were unable