The Tokyo Games will surely be a unique Olympics - the global sporting event that has persevered through wars, boycotts and now a pandemic over its 125-year modern history.
The Tokyo Olympics have already broken new ground because of the 12-month delay caused by the coronavirus pandemic, pushing the Games to an odd-numbered year for the first time.
But with no fans permitted in Japan, foreign or local, it has the distinction of being the first Games without spectators at venues.
There have been many other unusual editions of the Olympics in the past, however.
The United States and many of its allies boycotted the 1980 Moscow Games.
The Union of Soviet Socialist Republics and many of its allies reciprocated four years later by boycotting the 1984 Los Angeles Olympics.
Dozens of countries, mainly from Africa, boycotted the 1976 Montreal Games.
World War I and World War II forced the Olympics to be cancelled altogether, so there were no 1916, 1940 or 1944 Games.
The 1940 Games were supposed to be held in Tokyo but upon the return of the Olympics in 1948 London was chosen as host.
Tokyo had to wait until 1964 to host the Games for the first time.
The 1920 Olympics in Antwerp, Belgium, took place as the world was emerging from both World War I and a flu pandemic that killed more than 50 million people.
Another odd Olympic occurrence came at the 1956 Melbourne Games, when the equestrian events were held in Stockholm because of animal quarantine regulations in Australia.
Tragedy has also marked the Olympics, most notably when 11 members of the Israeli team were murdered by the Palestinian terrorist group Black September at the 1972 Munich Games and when a bomb exploded in the Olympic Park at the 1996 Atlanta Games.
Other host cities have turned down the right to host the Games.
The 1908 Olympics were awarded to Rome but they were relocated to London after the eruption of Mount Vesuvius, because the Italian government decided its financial resources would be better spent on rebuilding Naples.
Rome finally hosted the Games in 1960.
The 1936 Berlin Games has an especially controversial past - although they were awarded about two years before Adolf Hitler became dictator, they went ahead under Nazism.
Jesse Owens, an African American track great, won four gold medals, despite only being originally scheduled to compete in the 100 metres, 200m and long jump.
Marty Glickman and Sam Stoller had been presumed team members for the 4x100m relay.
However, they were replaced by Owens and Ralph Metcalfe, who won the race alongside Frank Wykoff and Foy Draper in world record time.
"What made the situation ugly was that Stoller and Glickman were the only Jews on the U.S. track team, and they returned to the United States as the only members of the squad who didn't compete," David Wallechinsky wrote in The Complete Book of the Olympics in 2012.
Australian Associated Press