Six moments of silence have been held in New York City, Washington, D.C., and Shanksville, Pennsylvania, to mark the moments when two planes crashed into the Twin Towers and took away nearly 3,000 lives 20 years ago. But 20 years after the terrorist attacks of September 2001, the War on Terror grinds along, frustrating, costly, and inconclusive in many ways. CGTN's Nathan King reports from Ground Zero.