Our cities are filled with buildings, roads, cars, buses, trains, bikes, parks and gardens. They are crisscrossed with power, water, sewage and transport systems. They are built by engineers, architects, planners, technologists, doctors, designers and artists. Our cities are shaped by our environment, our society and our culture. And each and every part is built on mathematics.

You can join Plus author and Charles Simonyi Professor for the Public Understanding of Science, Marcus du Sautoy, on a mathematical adventure in the city. Marcus and his team of mathemagicians are constructing walking tours of the city — but they need your help!

They are running a competition asking you to shine a mathematical spotlight on your city — it might be a piece of interesting architecture, a mathematical sculpture or the maths behind something more mundane, such as traffic lights — they want to hear from you! The competition opens on 4 April 2011 and closes 3 May 2011.

Winning entries will become part of a virtual mathscape of cities around the world and will help Marcus and his team develop their walking tours. And of course — you can win great prizes including subscriptions to Nature and becoming part of mathematical history by naming a mathematical object!

Hmmm... you could write about the maths behind architecture, engineering or traffic jams... there are so many possibilities! Where do you see the maths in your city?

For further information visit the Maths in the City site and follow them on Twitter and Facebook.