Still image from video shows the trail of a falling object above a residential apartment block in the Urals city of Chelyabinsk

The trail of a falling object is seen above a residential apartment block in the Urals city of Chelyabinsk, in this still image taken from video shot on February 15, 2013. A powerful blast rocked the Russian region of the Urals early on Friday with bright objects, identified as possible meteorites, falling from the sky, emergency officials said. REUTERS/OOO Spetszakaz (RUSSIA – Tags: ENVIRONMENT TPX IMAGES OF THE DAY)