 All of these walls, gates and earthworks were demolished in the nineteenth century ending with the destruction of Bern's greatest of its three guard towers, the Christoffelturm.Only the four central streets were lined with residential houses in late medieval times, while the rest of the area was devoted to agriculture and animal husbandry.While the entire old town of Bern is a UNESCO World Heritage Site, there are a number of buildings and fountains within the city that merit special mention.