The document describes how the cities of Sydney, Seoul, and Melbourne have changed over time from 1900 to 2000. Sydney transitioned from a port town in 1900 with many people walking to a modern city with cars and buses in 1950 and tall, unique buildings in 2000. Seoul similarly changed from a nucleated city with many walking in 1900 to a city with tall buildings and cars in 1950 and very modern, tall structures in 2000. Melbourne was initially a market town with horses in 1900, became more linear and nucleated with cars and buses replacing horses by 1950, and had many unique buildings and bridges along its river by 2000.