"Ahu" are stone platforms on which many moai sit. There are 313 known ahu and 125 of these carry moai. The biggest, Ahu Tongariki is 220 m (720 ft), and had the most (15) and tallest moai.
I wanted to make sure that this be the first scientific and technology revolution in history in which the public thoroughly discussed all the potential benefits and all the potential harms, in advance of the technology coming online and running its course.
It's difficult to gather information about the Vikings, because they never wrote down their own history. Most of what is known about Viking raids and customs comes from what their enemies documented about them.
