China opens one of the world's longest bridges

Chinese President Xi Jinping made a rare public appearance on Tuesday to open one of the world's longest sea bridges.

At a cost of $120 billion, it will link Hong Kong and Macau to southern China, the economic engine that powered Beijing's rise.

It is also a part of Xi's vision for China to lead the world in technological innovation.

But critics worry it's yet another sign of China's tightening grip over supposedly independent Hong Kong.