Binary, the base 2 number system, is how numbers are described and maths are carried out by computers. Gottfried Leibniz first described binary in 1703 but the people of the island of Mangareva in French Polynesia may have used binary long before that. Researchers believe they have discovered that the people used a mixture of base 10 and 2.
Different number bases in use by other cultures is nothing new, the Babylonians used base 60 and some Australian Aborigines use base 5 for example (personally i've always loved octal base 8). The people of Mangareva originally used base 10 like other Polynesians (and most other humans) but added binary to their counting.
The circle has turned full circle and the people of Mangareva now use base 10 only as a result of Western influences. Researchers have traced the use of binary through analysis of the language. Unfortunately no one on Mangareva still uses the binary system (except in their computers of course).
Interesting Mangareva is the way travellers can get to Pitcairn Island, the most remote of all British colonies. After flying to Mangareva from Tahiti Pitcairn Island is then reachable by boat, its a 32 hour journey though!