The course of this weekend's Boat Race stretches between Putney and Mortlake, covering a distance of four miles (6.8km) and passing under two bridges (Hammersmith and Barnes Railway Bridge).
Apart from three occasions in the 1800s when it ran in the opposite direction, the race always goes upstream, starting on the incoming flood tide which allows crews to row with the fastest current. If you watch the proceedings from the south side of the river (Putney, Barnes, Mortlake) you're on what's known as the Surrey side, also known as the Surrey station. The north bank is the Middlesex side or station (Fulham, Hammersmith, Chiswick).