Many runners taking on the 26.2-mile London Marathon route will be focused on keeping one foot going in front of the other.
But for those who do take a moment to look up, the flat and fast course, starting in Blackheath and finishing in front of Buckingham Palace, includes some of the capital’s top tourist sights.
:: The runners set off from three different start points and converge in Woolwich, where they will see the longest Georgian facade in Britain as they pass the Royal Artillery Barracks. This is one of three 2012 Olympic Games venues in Greenwich.
:: After six miles competitors will have Inigo Jones’ Queen’s House to their left, built in 1616 for Anne of Denmark. On their right is Christopher Wren’s Royal Naval Hospital.
:: Runners then pass the prime meridian in front of the National Maritime Museum, which was the start line for the Tour de France in July 2007.
:: Half a mile later the runners normally pass The Cutty Sark, the famous tea clipper built in 1869. But ongoing restoration work after a fire means the route will follow College Approach, Greenwich Church Street and Creek Road. The 250m lost here are made up at the Rotherhithe Tunnel roundabout and at Cabot Square, Canary Wharf.
:: At eight and a half miles athletes enter the Docklands area for the first time at Surrey Docks.
:: Two miles further on the route passes close to the Mayflower pub, where the pilgrim fathers met to set sail for America before relocating to Plymouth to avoid a mooring fee.
:: At the 12-mile mark competitors approach Tower Bridge. The bridge was built in 1894. All the machinery for raising and lowering the drawbridge remains original.
:: Runners then pass under Westferry Circus and head towards the Isle of Dogs peninsula. The area was given the name because Henry VIII kept his hunting dogs there.
:: At this point many runners will start to hit “the wall”, when the body runs out of fuel and starts using fat reserves. The 800ft (244m) One Canada Square tower at Canary Wharf – one of the largest single business developments in the world – may provide some distraction.
:: At mile 23 the course enters the City of London which has been the starting point for the Mini London Marathon since 2008.
:: One mile later the route passes Cleopatra’s Needle. The needle is one of a pair, the other standing in Central Park, New York, just a few feet from the New York Marathon course.
:: Runners pass the iconic London Eye, before the home stretch takes them in sight of the Palace of Westminster and Parliament Square – signs that the race is almost complete.
:: Finally the race comes to an end as competitors squeeze the last few drops of energy out of their legs to make it up the Mall to the finish line outside Buckingham Palace.