Located in Kailua, Ulupo Heiau is an ancient site that served as a religious site where native Hawaiians likely came for bountiful harvests, and then success in war. The stone platform of Ulupo Heiau measures 140 feet x 180 feet, while the walls were as high as 30 feet.;During its prime, Kailua was a political powerhouse in Oahu, rivaling Waialua. Crops of banana, sweet potato, and sugarcane grow in the area. Meanwhile fishermen harvested fish from the fishponds and the ocean.