Seoul, South Korea (CNN) -- On the surface, Seoul, the capital of economic powerhouse South Korea, is one of the most impressive cities in East Asia: Sprawling and prosperous, hi-tech and self confident. But eight times a year, the traffic comes to a halt and crowds disappear from the streets as an eerie wail resounds across the city: The sound is a siren, and this is the minbangui, or civil defense exercise, designed to drill the population against a possible strike. Seoul is a metropolis that lives in the gun sights of North Korea, one of the most dangerous states on the planet and just 40 miles (64 kilometers) north of downtown, yet Seoul residents have learned to live with the threat.
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Although no strangers to North Korean hostility, Seoul residents see this attack as different
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The sight of columns of smoke rising from an artillery strike sent a frisson of real fear
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It was the first such attack since the Korean War ended at midnight July 27, 1953
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Seoul itself lies in range of massed, long-range North Korean artillery
The 20th century @placeholder lasted three years and killed -- estimates vary -- between two and four million.