A powerful blast shook central Prague this morning, shattering windows in buildings hundreds of feet away and causing the evacuation of a large area. Up to 40 people were injured in the explosion, which police say was probably the result of a gas leak, the AP reports. The explosion badly damaged one building, located next to a film school, and authorities believe people are still trapped in the rubble. "Honestly, if I had been in my bed I would have been covered in glass," said one US student who was in a nearby building. (More Prague stories.)