Orongo is a former place of worship located on the crater rim of Rano Kau. Orongo is beside Rano Raraku the only place where the entrance with the park ticket is only allowed once. So make sure to not arrive just 5 min before closing, if you want to see this place without being in a hurry. Orongo is a kind of small village with many stone houses, which have been restored. You can see many of them from the outside.
The place is especially known for the birdman cult. According to tradition, there was a competition every year, to get the first egg of the sooty tern (manutara bird) from the offshore island on which the bird breed. To do that, the competitors had to climb down the cliff almost 300m from Orongo, then swim 1.5km to the island without being eaten by the sharks, find the egg, swim back, climb up the cliff and arrive with the undamaged egg in Orongo. The head of the tribe of the winner became king of Easter Island for the next 12 month
You cannot find any Moais in Orongo. But there was one here before and because of the importance of this place, a very special one. A moai of basalt and with many petroglyphs. The Moai was stolen by the Europeans and is currently in the British Museum. His name is Hoa Hakananaia and he hopes to return home someday.
If you want to know more details about the birdman cult, have a look here: