SEOUL, South Korea -- They came from all over the world, poles in hand, and feet ready to inch more than half a mile across a high wire strung over the Han River in a spine-tingling battle of balance, speed and high anxiety.As part of its annual city festival, the South Korean capital staged Thursday what was billed as the world's first high-wire championship, drawing 18 contestants from nine countries for three days of supreme feats of concentration.Each acrobat must navigate the 1.2-inch-thick wire that spans the river, with the top prize of $15,000 going to the person crossing it...