The Yanomamö live in large single houses that, in close juxtaposition, look like a giant circular lean-to with a large central plaza. Families live in quarters that are not separated by internal walls. This communal dwelling is constructed of poles lashed together to form a framework that is thatched with palm leaves. In higher elevations the house may be reduced in diameter to form a pitched roof to adapt to cooler temperatures. The Yanomamö traditionally located villages near small, nonnavigable streams; since about 1970, however, many Yanomamö have chosen to occupy large river sites to maintain easy contact with missionaries.