A time enthusiast from Cambridge says the skills needed to make sundials could die out because not enough young people are interested in studying them.
Dr Frank King says sundials are a combination of art and mathematics, but getting the next generation to learn about them is an uphill struggle.
- Click below for Matthew Hudson's report
You might think sundials were just a simple way of telling the time before we invented clocks and computers.
They can be simple. They can also be so complex you need a doctorate in extremely hard sums to fully understand them.
Fortunately Cambridge University Fellow Frank King is here to share his love and knowledge.
Dr Frank King said: "I like sundials because they represent a splendid interface between art and mathematics.
"You’ve got the two things going together and you absolutely can’t have a sundial which doesn’t have both."
Frank's in the right city. Cambridge has dozens of sundials in public places.
- Some are simple - and inaccurate - like the one known as a mastile tucked away on a 14th century church
- Others are complex like the polyhedron dial on the University's Downing site with 26 sides and 17 dials
ITV News Anglia's Matthew Hudson said: "Time for the history lesson. It's believed primitive people used their bodies and their shadows as simple sundials.
"We know from archaeology that the ancient Egyptians had them three and a half thousand years ago.
"They're mentioned in books of the Old Testament dating back to around 700bc.
"And the Roman writer Vitruvius complied a list of the all the types of sundial in his time."
- Some, like the dual dial high up on St Botolph's Church, go largely unnoticed
- Dr King's sundial on the Bath Stone wall of Pembroke College
Apparently the sundial on Selwyn College gives you the time under the Babylonian time system, the Italian time system and the French one - but only if you add the other two times together and divide by the thingy. Or something.
But in the 21st century, will they be joining the abacus and slide rule in the dustbin of mathematical history. Frank hopes not.
Dr King said: "Unquestionably there are still people ordering them. I get commissions quite frequently.
"So there are people who are interested in sundials today and once you explain how sundials work and the variety of things they can indicate, apart from the boring, not-quite-right clock time, then people will sit up and take notice."
A small but important part of what makes Cambridge beautiful. Maybe look out for sundials next time you're in the city.