Follow the link below to an interesting article about a civilisation that has managed to keep Western Civilisation at bay. They live on an island and do not take kindly to visitors. 

Now imagine you are charged with the task of making contact with them and winning their confidence.  You can fly over the island and drop one item. What would that be???

http://brightside.me/article/the-inhabitants-of-this-island-havent-allowed-outsiders-on-their-land-for-thousands-of-years-17505/