There is an unusual "Navel of the World" stone site bordering Ahu Te Pito Kura, near Anakena ...
... with a round water worn beach boulder similar to those found in New Zealand.
Rapanui today say the central round stone was brought by Hotu Matu'a from his native land.
Geologists consider the rock to be locally sourced, which coincides with earlier oral traditions.
They say that the rock was found by the clan that occupied Vinapu who used it as a boundary marker.
They lost it to the Miru clan, from the Northern clan alliance, who took it to Te Pito Kura as a war prize.
The fact that the stone is large and was naturally round indicated that it was charged with "mana" and could be used as a talisman.
The navel has iron and its magnetic polarity varies like many of the stones found in the coast of Vinapu.
Reference: http://en.wikipedia.org/wiki/Easter_Island#Navel_of_the_world