North Korea's barrage of missile tests and a recent underground nuclear blast have unnerved many South Koreans. Yet for all the scaremongering on the Korean peninsula, an all-out attack by either side is unlikely.
Six decades ago, communist North Korea caught South Korea and its American allies off guard with an invasion that sent more than 180,000 troops and 240 Soviet-made tanks storming across the frontier, setting off a war that devastated the Korean peninsula.
Such a surprise attack wouldn't be easy today: Tens of thousands of South Korean troops stand guard along the 154-mile (248-kilometer) border, the world's most fortified. Watchposts and barbed wire line roads heading south, and huge blocks of concrete are ready to be dropped to obstruct the advancement of communist tanks.
South Korea's 650,000 forces are bolstered by 28,500 American troops in the country. The U.S. also has F-16 jets and A-10 attack aircraft in South Korea, while its F-16s in Japan could reach North Korea in an hour.
"I'm sure that the North Koreans know very well that they cannot win," said Yang Moo-jin, a professor at Seoul's University of North Korean Studies.