Editing Easter Island (section)

===={{anchor|stone platforms}}Ahu (stone platforms)====
[[File:Hangaroa Moais.jpg|thumb|right|Two ahu at [[Hanga Roa]]. In foreground Ahu [[Ko Te Riku]] (with a [[pukao]] on its head). In the mid-ground is a side view of an [[#Ahu (stone platforms)| ahu]] with five moai showing retaining wall, platform, ramp and pavement. The Mataveri end of Hanga Roa is visible in the background with [[Rano Kau]] rising above it.]]

''Ahu'' are stone platforms. Varying greatly in layout, many were reworked during or after [[Moai#1722–1868 toppling of the moai|the ''huri mo'ai'' or ''statue-toppling'']] era; many became [[ossuary|ossuaries]], one was dynamited open, and [[Ahu Tongariki]] was swept inland by a [[tsunami]]. Of the 313 known ahu, 125 carried moai{{snd}}usually just one, probably because of the shortness of the moai period and transportation difficulties. [[Ahu Tongariki]], {{cvt|1|km|mi|spell=in}} from Rano Raraku, had the most and tallest moai, 15 in total.{{sfn |Diamond |2005 |p=80}} Other notable ahu with moai are [[Ahu Akivi]], restored in 1960 by [[William Mulloy]], Nau Nau at Anakena and Tahai. Some moai may have been made from wood and were lost.

The classic elements of ahu design are:
* A retaining rear wall several feet high, usually facing the sea
* A front wall made of rectangular basalt slabs called ''paenga''
* A fascia made of red scoria that went over the front wall (platforms built after 1300)
* A sloping ramp in the inland part of the platform, extending outward like wings
* A pavement of even-sized, round water-worn stones called ''poro''
* An alignment of stones before the ramp
* A paved plaza before the ahu. This was called ''marae''
* Inside the ahu was a fill of rubble.

On top of many ahu would have been:
* Moai on squarish "pedestals" looking inland, the ramp with the poro before them.
* Pukao or Hau Hiti Rau on the moai heads (platforms built after 1300).
* When a ceremony took place, "eyes" were placed on the statues. The whites of the eyes were made of coral, the iris was made of obsidian or red scoria.

Ahu evolved from the traditional Polynesian ''[[marae]]''. In this context, ''ahu'' referred to a small structure sometimes covered with a thatched roof where sacred objects, including statues, were stored. The ahu were usually adjacent to the marae or main central court where ceremonies took place, though on Easter Island, ahu and moai evolved to much greater size. There the marae is the unpaved plaza before the ahu. The biggest ahu is {{cvt|220|m|ft}} and holds 15 statues, some of which are {{cvt|9|m|ft}} high. The filling of an ahu was sourced locally (apart from broken, old moai, fragments of which have been used in the fill).<ref name="Heyerdahl 1961" /> Individual stones are mostly far smaller than the moai, so less work was needed to transport the raw material, but artificially leveling the terrain for the plaza and filling the ahu was laborious.

Ahu are found mostly on the coast, where they are distributed densely and fairly evenly. The exceptions are the western slopes of Mount [[Terevaka]] and the Rano Kau and [[Poike]] headlands, where they are much sparser. These are the three areas with the least low-lying coastal land and, apart from Poike, the furthest areas from Rano Raraku. One ahu with several moai was recorded on the cliffs at Rano Kau in the 1880s but had fallen to the beach before the [[Katherine Routledge|Routledge expedition]].<ref name=routledge/> At least three recorded on Poike in the 1930s have also since disappeared.<ref>{{Cite book |last=Lavachery |first=Henri |title=Ile de Paques |title-link=Henri Lavachery |publisher=Bernard Grasset |year=1935 |edition=1st |location=Paris |language=french }}</ref><ref>{{Cite journal |last=SEAGER THOMAS |first=Mike |author-link=Mike Seager Thomas |date=2019 |title=New Contextual Survey on Poike, 2019 |url=https://www.researchgate.net/publication/353577661 |journal=Landscapes of Construction Interim Reports |volume=15 |page=2 }}</ref>
[[File:Rapa nui cyark 2.jpg|thumb|right|A Hare Moa, a Chicken House, image cut from a [[3D scanner|laser scan]] collected by nonprofit [[CyArk]].]]