Prior to Russian contact, Aleuts maintained coastal villages and seasonal subsistence camps. Prime village locations had safe access to the sea, a number of important food resources close at hand, and often lookout locales from which offshore resources or attacking enemies could be spotted. Villages varied a great deal in size, from just a few families in one or two houses to many families in several houses. The homes were semisubterranean, roofed over with rafters of driftwood and whalebone, and covered with a layer of sod. With the coming of the Russians in the mid-1700s and the Americans a Century later, the Aleut population dwindled and settlements were consolidated. By the early twentieth century, houses were nearly all above-ground frame structures in which Nuclear families lived.