Peru's 10km wall of shame: rich and poor divided ()

There is a 10km wall in Lima that separates the richest neighbourhood in the city from the poorest. For some it is known as the ‘wall of shame’, for others its essential to security. What are the root causes of this massive monument to inequality, how is it that a low income person on one side of the wall is paying twice what their rich neighbour is, on the other side of the wall, for a glass of water