Han River

A general view shows the Gangnam area (t...A general view shows the Gangnam area (top) and Han river (C) within the city skyline of Seoul at dusk on February 4, 2014. With a population of some 25 million people, the metropolitan area of Seoul is one of the largest in the world.

Ed Jones/AFP

Seoul at dusk on Tuesday, with the Han river flowing through the centre. The metropolitan area of the capital of South Korea is one of the largest in the world, with a population of some 25m people.