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.