The 2016 Olympic Games officially start in Rio on Friday with the opening ceremony at the Maracana Stadium.
Athletes from 206 nations and a refugee team are in Brazil to compete in 28 sports and be watched by a global audience of billions.
The build-up has been dominated by a Russian doping scandal, the Zika virus and issues with the city's security, infrastructure and venues. But it is time for the sporting action to take centre stage. These are the Games of the 31st Olympiad but are the 28th to be held as those in 1916, 1940 and 1944 did not take place because of war.
When does it start? The Games - held in South America for the first time - officially take place between 5 and 21 August, but they have actually already started. The opening ceremony is at midnight BST on Friday night but the action kicked off two days ago with the women's football.Defending Olympic men's tennis champion Andy Murray will be Great Britain's flag bearer inside Rio's Maracana stadium on Friday. An estimated three billion people will watch the ceremony, which has taken five years to produce and includes 300 dancers, 5,000 volunteers and 12,000 costumes.
Who is taking part? There will be 10,500 athletes from a record 207 teams competing in Rio, including the Refugee Olympic Team, while it will be the first time Kosovo and South Sudan have taken part in the Games. The Refugee Olympic Team will compete under the Olympic flag and has 10 members - five from South Sudan, two from Syria, two from DR Congo and one from Ethiopia. With 554 athletes, the United States has the largest Olympic team, but 100m runner Etimoni Timuani is the only athlete from the South Pacific nation of Tuvalu. The Rio Games will be the first to feature Olympians born since the year 2000 - and the youngest is 13-year-old Nepalese swimmer Gaurika Singh.
About the actual sport. Competitions will take place across 32 venues in Rio, with football matches also scheduled for the cities of Belo Horizonte, Brasilia, Manaus, Salvador and Sao Paulo. There are 306 events in 28 Olympic sports but none are bigger than the 100m sprint final and the world's fastest man Usain Bolt. The Jamaican is aiming for an unprecedented triple triple, as he tries to win the 100m, 200m and 4x100m relay titles for the third time - and his battle with American sprinter Justin Gatlin is likely to be a highlight of the Games.
USA swimmer Michael Phelps, the most decorated Olympian of all time, will be looking to add to his 18 gold medals. American tennis player Serena Williams could win her fifth Olympic medal, while Team USA's star-studded basketball team will be aiming for their third consecutive gold. Brazil's Barcelona striker Neymar will once again carry the hopes of the home nation as they go for gold in the men's football. Among those who miss out are top tennis players Roger Federer and Stan Wawrinka, NBA stars Stephen Curry and LeBron James and a number of golfers.
What time are the big events? Rio is four hours behind the UK and most of the gold medal events will be late evening/early morning so be prepared to become a night owl or an early riser. Britain's first gold medal could go to Chris Froome or Lizzie Armitstead as they go in the men's and women's road race on Saturday and Sunday. Swimming dominates the early part of the Games with the track and field events starting on Friday, 12 August.
The highlight of the action inside the Olympic Stadium is the men's 100m final at 02:25 BST on Monday, 15 August, so set your alarm clocks. Saturday, 13 August sees a potential London 2012 'Super Saturday' repeat, with Ennis-Hill in the heptathlon, Farah in the 10,000m and Greg Rutherford in the long jump.