Click the image to see the story. Photo by Stéphane Guisard.
At least 288 stone moai statues once stood upon massive ahu or stone platforms, spaced approximately one-half mile apart in around the perimeter of the island. These Stone-Heads average 14 feet tall and 14 tons heavy, carved from Rano Raraku volcanic stone. It would have taken dozens or hundreds of people to drag the maois across the island; considering that the population probably stood around 3000, that's a pretty massive undertaking.
Anthropologists theorize that the inhabitants arrived on this once-forested island about 300AD, built the first maois about 500AD and the last ones about 1650AD. The culture that built the maoi began to self-destruct sometime after Dutch explorer Jakob Roggeveen found the island in 1722 and Cook's visit in 1774, when many of the maois had been toppled. The history of Rapa Nui that we know about is tragic and - like so many such stories - reflects poorly on human nature. Check out this wiki article to get an overview. It includes slavery and plague.
Here's a map of Rapa Nui, showing its location in the Pacific:
Click the image to see the Wikipedia article and a larger version of the map.
Anthropologists believe the statues personified the religious and political power of their ancestors. Ancient Polynesian religions often believed that such carved objects were repositories of sacred spirit, imbued with a magical spiritual essence called "mana" (recognize that, gamers?), and the design of these statues is similar to styles found elsewhere in Polynesia.
Enough history: Check out the beauty of this shot. The silent and still personification of all this painful history standing beneath the distant and timeless stars makes for a pretty picture, eh?