For 25 years, a busy junction at the centre of the Serbian capital of Belgrade has been dominated by the blackened shell of the former Yugoslav Ministry of Defence. It has been deliberately left as it was after Nato bombs destroyed it in 1999 during the Kosovo war. Yet now this shrine to Serbian nationalism is set to be torn down and redeveloped into a glitzy hotel and apartment complex. The investors are from, of all places, America — Belgrade’s old adversary, which twice in the 1990s led...