Despite the Olympic Games being considered as the modern celebration of humanity, it has had occasional moments that proved undesirable in the spirit of brotherhood and humanity. Here's five cases of those infamous events that marred the dignity of the Games, hence any possibility of repeat should be avoided at all cost specially at the now ongoing Olympic Games in Beijing, China that commenced on August 8, 2008 and ends on the 24th.
The Munich Massacre

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Two of the Israeli hostages talked to German negotiators
In allusion to post-war Germany, the 1972 Summer Olympics held in Munich was dubbed as the “Happy Games”, ironically it had turned out to be one of the most infamous Games in history. Delegation from Israel was taken hostage when terrorists from the Palestinian group known as Black September barged into the Olympic village, killing two right on site. When the ordeal transpired after 18 hours, a German police officer and the 11 Israeli hostages were gone. The games was momentarily suspended for a day but continued the next day.
1980 Summer Olympics Boycott
Despite of the Olympics being free from political interventions, the United States boycotted the 1980 Moscow Summer Olympics on grounds of Russia's invasion of Afghanistan. The historic boycott was well-supported that numerous other countries across the continents joined the United States' sentiment. Some of them though, allowed their athletes to compete own their own without using their country's respective flags. They used the Olympics flag instead. In 1984, the Union of Soviet and its allies such as Cuba and East Germany returned the favor by boycotting the next Olympics in Los Angeles, United States.
Ben Johnson

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Ben Johnson (center) during the 1988 Summer Olympics
Born in Jamaica but later moved to Canada where he joined the country's track and field team in all international competitions. A highly competitive sprinter, he won two bronze medals for Canada at the 1984 Summer Olympics in Los Angeles, United States. He seemed to improve with age as he later won world championships, beating Carl Lewis, the legendary American sprinter who kept beating him in many previous competitions. Lewis later successfully recaptured the world championship after beating Johnson and boldly predicted that the 100-m dash gold medal in the coming 1988 Summer Olympics in Seoul will never go to the later. Instead, Johnson won the gold, boasting that he could have run faster had he not raised his arms in celebration when he cross the finish line. Fans all over the world were convinced of Johnson's supremacy. But three days later, his blood was found positive of Furazabol, a performance-enhancing drug strictly against the roles of the Games. Consequently, he was stripped of his medals and world records he had previously held, making him an athletic superstar in recent memory to have fallen in disgrace.
East German Doping Program
East Germany kept on improving in their athletic performances which was dramatically concluded at the 1976 Summer Olympics in Montreal, Canada. East Germans received a total of 40 gold medals, more than twice of their winnings at the previous 1972 Olympics in Munich. People were less skeptical for they were a country of 17 million people after all. But all foul odors came out in 2000 when the former East German chief of sports program-Manfred Ewald - was found guilty of “intentional bodily harm of athletes” by doping some of their athletes with anabolic steroid that consequently altered their sexuality-under the reign of Ewald, East Germany amassed an incredible 160 gold medals in which some of those can now be refuted to be fraudulent.
Adolf Hitler
Despite of being aware of the Olympics' independence of world politics, Adolf Hitler exploited the 1936 Olympic Games in Berlin by being vocal about his insubstantial claim on the superiority of the Aryan race who were believed to be the ascendants of the Germans, thus their dominance over any other race in the world. However, in a 45-minute performance, an unknown grandson of a black slave, Jesse Owens embarrassed Hitler by doing a gold-winning and world record-setting performance in track and field. He won three gold medals for the United States. Hitler refused to shake hands with him at the medal podium.