An Audax is semi-competitive cycling event, aiming to cycle over a defined route within a maximum and minimum time. Routes are typically 200, 300, 400 or 600km. There are also shorter 'fun' events of 50 or 100km.
The pinnacle of Audax achievement is to ride the 1200km Paris-Brest-Paris, which is held every four years. It is not the longest or the hardest but it is certainly the biggest with over 3000 riders.
Go to the Audax UK website for national details.
Click on the image to go to the Cambridge Audax website for details of local rides.