Images of notable students were projected on university buildings
Thousands of people have taken part in global celebrations marking the 800th anniversary of Cambridge University.
A specially-commissioned light show charting the university's history kicked off the celebrations - which tied in with the start of a new term.
Church bell-ringers around the world also simultaneously played a new piece composed for the occasion.
Notable former Cambridge students include Oliver Cromwell, Isaac Newton, Charles Darwin and Stephen Hawking.
Thousands braved the cold to visit the launch of the celebrations at Senate House Yard, Cambridge.
Deputy vice-chancellor professor Jeremy Sanders said he was pleased with the "exuberant" atmosphere.
"There were lots of families. It's been very informal and friendly - it was lovely.
"This is all about what Cambridge has achieved for the world over hundreds of years."
The university, which has produced more Nobel Prize winners than any other institution, has organised a number of events throughout the year to mark the anniversary.
It was founded in 1209 after scholars from Oxford gathered to study at the ancient Roman trading post of Cambridge.
Cambridge now plays host to 18,000 students and has an annual turnover of almost £1bn.
It was home to some of the most significant scientific breakthroughs in history - including the splitting of the atom and the discovery of the structure of DNA.
The light show which was projected on to the Senate House and Old Schools was produced by artist Ross Ashton and contained images of iconic moments and illustrations by Downing College alumnus and former Children's Laureate Quentin Blake.
Mr Blake, whose new animated drawings of Isaac Newton and Charles Darwin were among on show, said he was looking forward to the year of celebrations.
He said: "We need to remind everybody of the history of this extraordinary place. It is wonderful and I am terribly privileged to be asked just to make a contribution to it."
Cambridge University prepares to celebrate its 800th birthday
Four churches in central Cambridge - Great St Mary's, St Bene't's, St Edward King and Martyr and St Andrew the Great, were among those worldwide which took part in the mass bell-ringing and performed a piece by Clare College alumnus Phil Earis.
Although academics are not sure of the exact date of the founding, the felt it was best to start the birthday celebrations when the students returned from their holidays.
Other events include a Charles Darwin festival and a science festival.
A Festival of Ideas is planned for October, while a closing ceremony will be held the following month.
A special fund has been created by the university to support other events proposed by individual departments, colleges and student groups.
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