This archeological site, discovered after flooding from a tropical storm in 1975, is the island's most important. Dating from AD 300–700, it includes nine playing fields used for a ritual ball game that some think was similar to soccer. The fields are bordered by smooth stones, some of which are engraved with petroglyphs that might have ceremonial or astronomical significance. In the eye-catching Plaza de Estrella (Plaza of the Star), stones are arranged in a pattern resembling a rising sun, perhaps used to chart the seasons. A village with thatched huts has been reconstructed. Visit the small museum before taking a walking tour of the site.