Teheran (named after a visit by the mayor of Teheran, before this boulevard became South Korea’s Silicon Valley) is a canyon of glass and steel, and a visceral reminder of the economic powerhouse the country is today. The quickest way to get here from north of the river is to take the metro. One station has a virtual Tesco. Using the touch-screen simulation of supermarket shelves, you can do your grocery shopping and have it delivered by the time you get home. But there are also more sobering offerings. Every station has several glass cabinets lined with gas masks. Is this in the event of a random fire, or in case of an even more random attack from South Korea’s saber rattling northern neighbor? The week before my visit, North Korea issued a statement reminding the world that it could reduce Seoul to ashes in three to four minutes. Despite their fabulous prosperity and hyper consumption, that prospect is always somewhere in the back of the minds of Seoul’s citizens.