On Location Video: World Cup 2014 will basically be a giant robotics show

A police drone flies over a protest in Rio de Janeiro</p>

A police drone flies over a protest in Rio de Janeiro

RIO DE JANEIRO, Brazil — With simmering protests, a surge in violence and less than three months to go till the World Cup, Rio de Janeiro police have introduced a host of new tactics that seem right out of science fiction.

Each hosting city has spent about $90 million on surveillance drones, explosive-detecting robots, camera glasses and other equipment.

But is it making the city safer?