Here is a look at the Venice film festival, the world's oldest, which starts on Wednesday on the Lido seafront and promises two documentaries among the 20 titles competing for the top Golden Lion prize.

The world premiere of Mexican film director Alfonso Cuaron's "Gravity", starring Sandra Bullock and George Clooney, will open the festival, however it is not part of the competition.

* The first "Esposizione d'Arte Cinematografica" was in 1932. The first film to be shown was Rouben Mamoulian's "Dr. Jekyll and Mr. Hyde", screened in August of that year. The second festival, held in August 1934, included the first competition. Nineteen countries took part with more than 300 accredited journalists. The "Coppa Mussolini", named for the Italian dictator, was introduced for best foreign film and best Italian film.

* The festival was held three times during World War Two, from 1940 to 1942, but they are not counted in the total number of festivals. Participation was limited to countries in the Axis and their sympathizers. A short festival was held in 1946.

* The 1947 festival was held at the Ducal Palace. It saw the return of the Soviet Union and the new "popular democracies" including Czechoslovakia, which won first prize for "Sirena" by Karel Stekly.

* During the 1950s, the festival experienced a period of international expansion, with the inclusion of films from Japan and India. Japanese cinema became well known in the West largely thanks to the Golden Lion awarded to Akira Kurosawa's "Rashomon" in 1951, and through the Silver Lions won by "Ugetsu Monogatari" (1953) and "Sansho Dayu" (1954) by Kenji Mizoguchi.

* Director Ang Lee's sexually explicit spy thriller "Lust, Caution" was a surprise winner of the top award at the 2007 festival, just two years after he won with "Brokeback Mountain".

* The 2012 Golden Lion award was won by a South Korean movie, "Pieta", an ultra-violent story of a loan shark confronted by a mysterious woman claiming to be his mother. The other big winner was Paul Thomas Anderson's "The Master", loosely based on the early days of Scientology, which earned him a Silver Lion for best director and a joint best actor award for Philip Seymour Hoffman and Joaquin Phoenix.

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