Silicon Valley's giants take talent hunt to Cambridge

There are more than 4,500 high-tech firms in Cambridge

When you step off the train here and walk into the city square outside the railway station, you will not see the spires of King’s College Chapel or the turrets atop the Trinity Great Court. The University of Cambridge is still a cab ride away. But you will see a stone and glass office building with a rooftop patio. This is where Amazon designs its flying drones.

Just down the block, inside a stone building of its own, Microsoft is designing some sort of computer chip for artificial intelligence. And if you keep walking, you will soon reach a third building,