Most cities build their boldest works of architecture around expos. Milan created their Bosco Verticale right ahead of Expo 2015:
My home city of Montreal built Habitat ahead of Expo 67:
Milan’s vertical garden and how it hasn’t been copied as grand. ^[Tree-Covered Skyscrapers Aren’t Actually That Green - YouTube https://www.youtube.com/watch?v=wFNDfSa7Ak8]
See if Alexandra Allen has something written about this