While there is a lot of persistence in the patterns of prosperity we see around us today, these patterns are not unchanging or immutable. First, as we have already emphasized, most of current world inequality emerged since the late eighteenth century, following on the tails of the Industrial Revolution. Not only were gaps in prosperity much smaller as late as the middle of the eighteenth century, but the rankings which have been so stable since then are not the same when we go further back in history. In the Americas, for example, the ranking we see for the last hundred and fifty years was completely different five hundred years ago. Second, many nations have experienced several decades of rapid growth, such as much of East Asia since the Second World War and, more recently, China. Many of these subsequently saw that growth go into reverse. Argentina, for example, grew rapidly for five decades up until 1920, becoming one of the richest countries in the world, but then started a long slide. The Soviet Union is an even more noteworthy example, growing rapidly between 1930 and 1970, but subsequently experiencing a rapid collapse.