The Venice Film Festival marks its 70th edition with films starring George Clooney and Sandra Bullock as astronauts adrift in space, Scarlett Johanseen as a seductive alien roaming the Scottish countryside and Judi Dench as a single Roman Catholic woman searching for a son she was forced to give up decades before. The Festival will take place from 28 August until 7 September. Festival director Alberto Barbera concedes that many of the films in the line-up announced Thursday are bleak in their outlook, particularly the ones from countries hit by the ongoing economic crisis. \"Cinema mirrors reality, so we can\'t complain if auteur films today gives us an image of our times that is not consoling,\" Barbera told a news conference. Twenty films will vie for the coveted Golden Lion at the world\'s oldest film festival, with a jury headed by Bernardo Bertolucci. The films include Terry Gilliam\'s \"The Zero Theorem,\" starring Christoph Waltz as a reclusive computer genius, and Peter Landesman\'s \"Parkland,\" which examines the chaotic events at Dallas\' Parkland hospital the day John F. Kennedy was assassinated. Indie director Kelly Reichardt returns to Venice with \"Night Moves,\" starring Jesse Eisenberg, Dakota Fanning and Peter Sarsgaard as environmental activists plotting to blow up a dam. Johansson appears in Jonathan Glazer\'s highly anticipated science fiction thriller \"Under the Skin,\" while Dench stars in Stephen Frears\' \"Philomena.\" Director Alfonso Cuaron\'s \"Gravity,\" starring Clooney and Bullock, will open the festival and is among 17 films showing out of competition. Thierry Ragobert\'s documentary \"Amazonia\" closes the event on September 7. The Venice Film Festival is strong on independent, auteur films and light on blockbusters, a delicate point for organisers competing with Cannes, which shows in the spring, and Toronto, which overlaps with Venice. \"Venice on paper takes more risks — for example, taking two documentaries in competition, a first by any festival, and organising an auteur cinema to support and promote these films,\" said Barbera. Barbera, who is in the second year of a new mandate after directing the festival from 1998 to 2002, is intent on securing the festival\'s role as a launch pad for new films. Venice has premiered such films as the \"The Hurt Locker,\" which went on to win an Academy Award for best film, and the highly acclaimed \"Black Swan.\" The festival will showcase 53 new feature films, all but two world premieres, with 33 countries represented in the overall selection, which also includes sections on new trends and short films. Of the 20 films competing for the Golden Lion, five are American, four British and three Italian. Arab directors participating in this year\'s edition include Algerian Merzak Allouache, presenting \"Es-Stouh,\" and Morrocan Gianni Borgna and Enrico Menduni, showcasing their documentary \"L\'Africa di Pasolini.\" The festival is also sponsoring a workshop to support African films in post-production, which will include \"The Cat\" by Egypt\'s Ibrahim El-Batout and \"Challat Tunes\" by Tunisia\'s Kaouther Ben Hania. Ibrahim El-Batout participated in the 2012 Festival, premiering an independent film entitled \"Winter of Discontent.\" The film portrays the lives of a state security officer, a political activist, and a journalist during the 18-day revolution that led to the ouster of former president Hosni Mubarak in February 2011. The lineup also includes films by three Oscar-winning directors: Hayao Miyazaki with an animated film about a Japanese fighter plane designer, Errol Morris with a documentary about former U.S. Defense Secretary Donald Rumsfeld, and Poland\'s Andrzej Wajda with a movie depicting the life of Solidarity leader Lech Walesa. The first two are in competition. The other documentary in competition is Gianfranco Rosi\'s \"Sacro GRA,\" about life on the highway that rings Rome. Three previous Golden Lion winners are returning to the Lido. They include Italy\'s Gianni Amelio with \"L\'intrepido,\" or \"The Intrepid,\" and Taiwan-based director Tsai Ming-liang with \"Stray Dogs,\" both in competition. Last year\'s winner, Kim Ki-duk, will premiere \"Moebius,\" his follow-up to \"Pieta\" which generated controversy at home in South Korea for its graphic content.