From Hanga Roa, the six-km trip south to Orongo and the vast, circular crater of Rano Kau can be done in a morning, but take along a lunch and make a day of it if you have the time. On the way, just past the Iorana Hotel, at the foot of the cliff near the water, is Ana Kai Tangata, the Cannibal Cave. Since the cave faces west, the paintings of birds gracing the cave's ceiling are best photographed in the afternoon.
The road to Orongo swings left and up the side of 316-meter Rano Kau, but if you're on foot look for the shady footpath on the right which begins immediately after the CONAF office and climbs through the forest. Otherwise, take a taxi from Hanga Roa to the summit and walk back. Guavas (an edible round yellow fruit with a pink interior) grow wild along the side of the road to Orongo.
An admission of US$60 (US$20 for Chilean nationals) is charged at an office up at the entrance to Orongo. The entry fee may seem stiff, but all the other sites on the island are included, and CONAF is desperately short of funds needed to protect and maintain Easter Island's monuments.
Orongo was the main ceremonial center on the island and many high-relief carvings of frigate bird-headed men are on the rock outcrops. The 47 basalt slab dwellings here (restored by Dr. Mulloy in 1974-1976) were used by island chiefs and participants during the birdman festivals, the last of which occurred in 1866. Every September a race was staged to the farthest offshore island, Motu Nui, to find the first egg of the migratory sooty tern (manutara). The winning swimmer was proclaimed birdman (tangata manu) and thought to have supernatural powers.
Some of the highest sea cliffs on the island are on Orongo's south side and it's risky to try to hike around the volcano. The island's original vegetation is best preserved inside the crater itself and a good alternative is to hike the 250 meters down to the water's edge. The trail begins at the signposted viewpoint over Rano Kao. On your way back to town, it's possible to cut back toward Ahu Vinapu along the south side of the airstrip.