when do they have the olympics?
Once every two years
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 The Games have grown so much that nearly every nation is now represented . This growth has created numerous challenges and controversies , including boycotts , doping , bribery , and a terrorist attack in 1972 . Every two years the Olympics and its media exposure provide unknown athletes with the chance to attain national and sometimes international fame . The Games also constitute an opportunity for the host city and country to showcase themselves to the world . 

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 The modern Olympic Games or Olympics ( French : Jeux olympiques ) are the leading international sporting event featuring summer and winter sports competitions in which thousands of athletes from around the world participate in a variety of competitions . The Olympic Games are considered to be the world 's foremost sports competition with more than 200 nations participating . The Olympic Games are held every four years , with the Summer and Winter Games alternating by occurring every four years but two years apart . 

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 The Olympic opening ceremonies represent the official commencement of an Olympic Games . In recent Olympics , athletic competition began prior to the opening ceremonies . For example , the football competitions for both men and women at the 2008 Summer Olympics began two days prior ( August 6 ) to the opening ceremonies . As mandated by the Olympic Charter , various elements frame the Opening Ceremonies of a celebration of the Olympic Games . Most of these rituals were canonized at the 1920 Summer Olympics in Antwerp , Belgium . 

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 The evolution of the Olympic Movement during the 20th and 21st centuries has resulted in several changes to the Olympic Games . Some of these adjustments include the creation of the Winter Olympic Games for ice and winter sports , the Paralympic Games for athletes with a disability , and the Youth Olympic Games for teenage athletes . The IOC has had to adapt to a variety of economic , political , and technological advancements . As a result , the Olympics has shifted away from pure amateurism , as envisioned by Coubertin , to allowing participation of professional athletes . The growing importance of mass media created the issue of corporate sponsorship and commercialization of the Games . World wars led to the cancellation of the 1916 , 1940 , and 1944 Games . Large boycotts during the Cold War limited participation in the 1980 and 1984 Games . 

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 Months before each Games , the Olympic Flame is lit in Olympia in a ceremony that reflects ancient Greek rituals . A female performer , acting as a priestess , ignites a torch by placing it inside a parabolic mirror which focuses the sun 's rays ; she then lights the torch of the first relay bearer , thus initiating the Olympic torch relay that will carry the flame to the host city 's Olympic stadium , where it plays an important role in the opening ceremony . Though the flame has been an Olympic symbol since 1928 , the torch relay was only introduced at the 1936 Summer Games . 
