It's Stephen Hawking's 70th birthday this week and the University of Cambridge is celebrating with a star studded conference in his honour. If it's going to be as exciting as his 60th birthday, and it definitely looks like it will, then we're in for a treat! We'll be giving you articles and podcasts from the conference soon, but in the meantime, here's what we did for his 60th:

We're proud to present Professor Stephen Hawking's symposium address for his 60th birthday.

Astronomer Royal Sir Martin Rees gives Plus a whistlestop tour of some of the more extraordinary features of our cosmos, and explains how lucky we are that the universe is the way it is.

Nobel Prizewinning Physicist Professor Gerardus 't Hooft has always been fascinated by the mathematical mysteries of nature. He tells Plus about his early life, and what our Universe might really be like.

Will we ever be able to make computers that think and feel? If not, why not? And what has all this got to do with tiles? Plus talks to Sir Roger Penrose about all this and more.

What happens when one black hole meets another? Professor Kip Thorne shows us how to eavesdrop on these cosmic events by watching for telltale gravitational waves.