Alfred-Philippe Roll, Portrait of Adolphe Alphand the civil engineer who remodelled Paris under Baron Hausmann. We may marvel at the wide Boulevards he created today, but the real reason for them wasn’t aesthetic, it was to quell rebellion quickly such as the 1871 Paris Commune.

Mass control of people through road planning – you could position artilery at one of the radiating junctions and control miles of streets – and march armies down them rather than the small guerilla-friendly streets that helped the 1848 Commune.