Video shows moment Mexico City metro overpass collapses

An overpass carrying a subway train has collapsed in Mexico City, killing at least 23 people, according to local government officials. CCTV surveillance footage shows the moment the overpass collapsed. CNN’s Matt Rivers reports.An overpass carrying a subway train has collapsed in Mexico City, killing at least 23 people, according to local government officials. CCTV surveillance footage shows the moment the overpass collapsed. CNN’s Matt Rivers reports.