"In the nineteenth century some parts of the world were unexplored, but there was almost no restriction on travel. Up to 1914 you did not need a passport for any country except Russia. The European emigrant, if he could scrape together a few pounds for the passage, simply set sail for America or Australia, and when he got there no questions were asked. In the eighteenth century it had been quite normal and safe to travel in a country with which your own country was at war."