The superintendent of the Los Angeles school district ordered all L.A. schools shut down due to an unspecified emailed terrorist threat. Terrorists rarely send warnings before they attack, but the superintendent isn't taking any chances.
The closures affects 640,000 students from kindergarten through 12th grades at 900 schools. All 900 schools will be canvased to search for bombs. The Los Angeles school district is the 2nd largest in the country.