Residents reported hearing an explosion near a busy Midtown intersection Monday night, prompting a response from Atlanta Fire Rescue crews who later found and extinguished a small underground fire that knocked out power to thousands of customers.

Preliminary findings in the fatal explosion at the Bristol Health & Rehab Center appears to center on the condition of the natural gas line in the building.

Wednesday marks 40 years since the Space Shuttle Challenger disaster. On Jan. 28, 1986, the Challenger took off from the Kennedy Space Center in Florida. But just 73 seconds after lift-off, it exploded.