Famous for its split-screen display, eccentric student contestants, difficult questions and intimidating host, University Challenge has been an almost constant fixture on our screens for more than 50 years.
The programme has clocked up over 1,600 episodes and regularly pulls in audiences of 3 million. Its impressive reign continues into the online era, despite barely changing the format, its staging or the rules of the show.
What are the secrets of its extraordinary success? Is it the questions, the contestants, or the format?