The £400 million palace of Turkey’s President Erdogan is the biggest in the world. It is also a monstrosity. Thirty times the size of the White House, all the seats of government of Turkey’s Nato allies could be contained inside its vast marble halls and endless corridors. No wonder the sprawling modernist structure is compared to the People’s Palace built by Romania’s dictator Nicolae Ceausescu. It actually looks more like a massive public lavatory. Saddam himself would blanch at the silk wallpaper in the bathrooms, the cabinets displaying gold inlaid glasses that cost £250 each, and the 63 lifts. The...