Two types of houses are known from the past: "hare paenga", a house with an elliptical foundation, made with basalt slabs and covered with a thatched roof that resembled an overturned boat, and "hare oka", a round stone structure. Related stone structures called "Tupa" look very similar to the "hare oka", except that the "Tupa" were inhabited by astronomer-priests and located near the coast, where the movements of the stars could be easily observed. Settlements also contain "hare moa" ("chicken house"), oblong stone structures that housed chickens. The houses at the ceremonial village of Orongo are unique in that they are shaped like "hare paenga" but are made entirely of flat basalt slabs found inside Rano Kao crater. The entrances to all the houses are very low, and entry requires crawling.