The ruined heart of an American city, laid waste by economic collapse, is explored by Paul Mason; Mary Harper visits a hotel in Nairobi that's become a little piece of Somalia; from a South African prison, Hamilton Wende tells an inspiring tale of guilt and redemption; there's an explosion in modern art in the Turkish city of Istanbul, but Rosie Goldsmith's been finding out that not everyone's happy with that. And our correspondent David Willis struggles to embrace America's passion for Halloween.