Critical Mass is an international event that takes place in more than 200 cities around the world the last Friday of every month. The idea is for a mass of cyclists to take to the roads together in order to force polluting cars and motorcycles to give them more space. The next Critical Mass event takes place on Friday 24 September and in Rome the meeting place is at Piazzale Ostiense at 18.00.

For more information, www.tmcrew.org/eco/bike/criticalmassroma/