In the middle of Seoul, there is a river that spent half a century in the dark. The Cheonggyecheon stream once ran openly through the heart of the city, but in the decades after the war it became polluted and crowded with shacks, so the city buried it. Concrete went over the water, and by the 1970s an elevated highway roared above the concrete. The river became a rumour underneath the traffic.
Then, in 2003, Seoul did something that seemed almost backwards: it began demolishing the highway to dig the river back out. Engineers removed the roads, restored almost six kilometres of the stream, and built walkways, stepping stones, and bridges along the banks. Critics said the city was destroying useful infrastructure for a decoration. The project pressed on anyway, and the stream reopened in 2005.
The results surprised even the optimists. Fish, birds, and insects returned to water that had not seen sunlight in fifty years. Summer temperatures along the stream measured several degrees cooler than on the parallel roads nearby, a natural air conditioner running through the densest part of the city. Today millions of people walk the banks every year, many of them too young to remember that their favourite place in Seoul was once the underside of a highway.
