Dubai's Burj Khalifa, the world’s tallest building is illuminated during festivities marking the one-year countdown to Expo 2020. Giuseppe Cacace / AFP 
Dubai's Burj Khalifa, the world’s tallest building is illuminated during festivities marking the one-year countdown to Expo 2020. Giuseppe Cacace / AFP 

Soft power and prestige: the allure of world Expos endures