BEIJING – A 13-year-old American boy campaigning to turn the demilitarized zone between North and South Korea into a peace park tried to get the Chinese president's attention Monday, staging a brief protest near Tiananmen Square before being led away by police. Jonathan Lee unfurled a sign saying "peace treaty" and "nuclear free DMZ children's peace forest" as he stood outside Tiananmen Gate just north of the square in central Beijing.