(BBC) 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.
Brazilian supermodel Gisele Bundchen and Briton Dame Judi Dench are confirmed to have roles in the production before the 207 competing teams take part in the Parade of Nations.
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.
What about Russia?
The build-up to Rio has been overshadowed by events in Russia, after the World Anti-Doping Agency (Wada) report into state-sponsored doping in the country.
It seemed at one stage that no Russian athletes would be at the Games after Wada recommended a blanket ban.
But the International Olympic Committee (IOC) said individual sporting federations must rule on whether Russians can compete.
Their decisions were then ratified by a three-person IOC panel.
On Thursday, the IOC cleared 271 Russian athletes from the country’s original entry list of 389, though 67 of its 68 track and field athletes have been barred by the sport’s governing body.