The Head of the River Race is one of the London's longest running sporting traditions. Every spring, 400 crews from around the globe take to the waters of London's famous river Thames to compete in this historic boating event.The Head of the River Race (HORR) was started in 1926 by Cambridge and Tideway oarsman Steve Fairbairn. It was conceived as a way for crews to practice long rows during winter, in preparation for the summer regatta. The annual event now sees hundreds of boats, each manned by eight men, row over the 4.25 mile (6.8km) championship course from Mortlake to Putney.It is customary for the previous year's winner to start first. They are followed at 10-second intervals by other crews in finishing order and finally, the new entries start in alphabetical order.