women. Women had not previously been able to compete in team foil or saber events, although women's team épée and men's team foil were dropped for these Games. Marathon swimming events, over the distance of 10 km (6.2 mi), were added. In addition, the doubles events in table tennis were replaced by team events. American swimmer Michael Phelps set a record for gold medals at a single Games with eight, and tied the record of most gold medals by a single competitor previously held by both Heiden and Scherbo. Another major star of the Games was Jamaican sprinter Usain Bolt, who became the first male athlete ever to set world records in the finals of both the 100 and 200 metres in the same Games. Equestrian events were held in Hong Kong.
London held the 2012 Summer Olympics, becoming the first city to host the Games three times. In his closing address Jacques Rogge described the Games as "Happy and Glorious". The host nation won 29 gold medals, the best haul for Great Britain since the 1908 Games in London. The United States returned to the top of the medal table after China dominated in 2008. The IOC had removed baseball and softball from the 2012 program. On a commercial level the Games were successful as they were the first in history to completely sell out every ticket, with as many as 1 million applications for 40,000 tickets for both the Opening Ceremony and the 100m Men's Sprint Final. Such was the demand for tickets to all levels of each event, there was controversy when seats set aside for sponsors and National Delegations went unused in the early days. A system of reallocation was put in place so the empty seats were filled throughout the Games.
Rio de Janeiro, Brazil hosted the 2016 Summer Olympics, becoming the third city in the Southern Hemisphere to host the Olympic Games after Melbourne, Australia, in 1956 and Sydney, Australia, in 2000, and the first South American city to host the Olympics. The preparation for these Games was overshadowed by controversies, including the instability of Brazil's federal government; the country's economic crisis; health and safety concerns surrounding the Zika virus and significant pollution in the Guanabara Bay; and a state-sponsored doping scandal involving Russia, which affected the participation of its athletes in the Games. Tokyo, Japan will host the 2020 Summer Olympics, making it the first Asian city to host the Olympic Games twice.
Forty-two sports, spanning 55 disciplines, have been part of the Olympic program at one point or another. Twenty-eight sports have comprised the schedule for three of the recent games, 2000, 2004, and 2008 Summer Olympics. Due to the removal of baseball and softball, there was a total of twenty-six sports in the 2012 Games.
The various Olympic Sports federations are grouped under a common umbrella association, called the Association of Summer Olympic International Federations (ASOIF).
For individual sports, competitors typically qualify by attaining a certain place in a major international event or on the IF's ranking list. There is a general rule that a maximum of three individual athletes may represent each nation per competition. National Olympic Committees (NOCs) may enter a limited number of qualified competitors in each event, and the NOC decides which qualified competitors to select as representatives in each event if more have attained the benchmark than can be entered.
Nations most often qualify teams for team sports through continental qualifying tournaments, in which each continental association is given a certain number of spots in the Olympic tournament. Each nation may be represented by no more than one team per competition; a team consists of just two people in some sports.
Summer Olympic sports are divided into five categories (A – E) based on popularity, gauged by six criteria: television viewing figures (40%), internet popularity (20%), public surveys (15%), ticket requests (10%), press coverage (10%), and number of national federations (5%). The category of a sport determines the share of Olympic revenue received by that spo