The 2020 Olympic Games in Tokyo are the second time the Summer Games are held in that city.  The first time was in 1964.  Before that, the XIIth Olympic Games had been planned for Tokyo in 1940 but were cancelled due to the Second World War.

After the start of the modern Olympic Games in 1896, most Games took place in Europe. Maybe that was logical, since the tradition of a peaceful sport competition has its origin in ancient Greece, where one of the objectives was to promote good relations between Greek city states.

Since the end of the Second World War, the Games have been spread more evenly between the continents, except Africa, where they have never taken place. It is interesting to note that after Rio, the next three Games will occur in Asia.

Since 1994, the Winter Olympics do not happen in the same year as the Summer Olympics. Both series are organized on a 4-year cycle, but the Winter Games are offset by 2 years with respect to the Summer Games.

Several cities have hosted the Olympic Games more than once.  Athens and London have each hosted the Summer Games three times.  Innsbruck (Austria), St-Moritz (Switzerland) and Lake Placid (USA) have had the Winter Games twice, while Los Angeles and Paris have each been host to the Summer Games twice.

If things go according to plan, Beijing will become the first city to have hosted the Summer Olympic Games (in 2008) as well as the Winter Games (in 2022).

SummerGames

Winter Games

Year	No.	City	Country	Continent
1896	I	Athens	Greece	Europe
1900	II	Paris	France	Europe
1904	III	St. Louis	United States	North America
1906	Intercalated	Athens	Greece	Europe
1908	IV	London	United Kingdom	Europe
1912	V	Stockholm	Sweden	Europe
1916	VI	Cancelled (First World War)
1920	VII	Antwerp	Belgium	Europe
1924	I	Chamonix	France	Europe
1924	VIII	Paris	France	Europe
1928	II	St-Moritz	Switzerland	Europe
1928	IX	Amsterdam	Netherlands	Europe
1932	III	Lake Placid	United States	North America
1932	X	Los Angeles	United States	North America
1936	IV	Garmisch-Partenkirchen	Germany	Europe
1936	XI	Berlin	Germany	Europe
1940	V	Cancelled (Second World War)
1940	XII	Cancelled (Second World War)
1944	V	Cancelled (Second World War)
1944	XIII	Cancelled (Second World War)
1948	V	St-Moritz	Switzerland	Europe
1948	XIV	London	United Kingdom	Europe
1952	VI	Oslo	Norway	Europe
1952	XV	Helsinki	Finland	Europe
1956	VII	Cortina d’Ampezzo	Italy	Europe
1956	XVI	Melbourne	Australia	Oceania
1960	VIII	Squaw Valley	United States	North America
1960	XVII	Rome	Italy	Europe
1964	IX	Innsbruck	Austria	Europe
1964	XVIII	Tokyo	Japan	Asia
1968	X	Grenoble	France	Europe
1968	XIX	Mexico	Mexico	North America
1972	XI	Sapporo	Japan	Asia
1972	XX	Munich	West Germany	Europe
1976	XII	Innsbruck	Austria	Europe
1976	XXI	Montreal	Canada	North America
1980	XIII	Lake Placid	United States	North America
1980	XXII	Moscow	Soviet Union	Europe
1984	XIV	Sarajevo	Yugoslavia	Europe
1984	XXIII	Los Angeles	United States	North America
1988	XV	Calgary	Canada	North America
1988	XXIV	Seoul	South Korea	Asia
1992	XVI	Albertville	France	Europe
1992	XXV	Barcelona	Spain	Europe
1994	XVII	Lillehammer	Norway	Europe
1996	XXVI	Atlanta	United States	North America
1998	XVIII	Nagano	Japan	Asia
2000	XXVII	Sydney	Australia	Oceania
2002	XIX	Salt Lake City	United States	North America
2004	XXVIII	Athens	Greece	Europe
2006	XX	Turin	Italy	Europe
2008	XXIX	Beijing	China	Asia
2010	XXI	Vancouver	Canada	North America
2012	XXX	London	United Kingdom	Europe
2014	XXII	Sochi	Russia	Europe
2016	XXXI	Rio de Janeiro	Brazil	South America
2018	XXIII	Pyeongchang	South Korea	Asia
2020	XXXII	Tokyo	Japan	Asia
2022	XXIV	Beijing	China	Asia