The island of Tanna can be found in the Tafea Province of Vanuatu, a cluster of islands about a thousand miles east of Australia in the South Pacific Ocean. It's really tiny, but manages to house a population of roughly 28,000. About a thousand of them were recruited to the army in the Second World War, which is probably what lead to...well. There are apparently a lot of cargo cults (they happen when the decadent capitalist West interacts with uncolonised tribes) on the island, but the most enduring has been the worship of John Frum, an American World War II serviceman who people think will bring wealth and prosperity if they follow him. And who may not actually have existed. He's alternately portrayed as black or white, always in military fatigues, and is the subject of some devotion. Whilst the islanders did get visits from a nearby US army base, some contend he was a vision convincing them to give up Western influence (money, education, religion) so white people would leave and black people could rule the New Hebrides.
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/