 Between the 18th and mid-19th centuries Orongo was the centre of a birdman cult whose defining ritual was an annual race to bring the first "manutara" (sooty tern) egg back undamaged from the nearby islet of Motu Nui to Orongo.The race was very dangerous, and hunters often fell to their deaths from the cliff face or were killed by sharks.The site has numerous petroglyphs, mainly of "tangata manu" (birdmen) which may have been carved to commemorate some of the winners of this race.