At least 11 people are feared dead after the collapse of two high-rise buildings in downtown Rio de Janeiro. Emergency rescue workers were scrambling to dig out any survivors, and managed to free five people. The buildings, one 20 stories tall, crushed a four-story construction site nearby, and buried the surrounding streets and cars in rubble and dust. Officials are uncertain of a cause, but area witnesses reported smelling gas before the buildings collapsed. "It was like an earthquake," a witness told the BBC. First, some pieces of the buildings started to fall down. People started to run. And then it all fell down at once." (More collapse stories.)