The Cornell Environmental Film Festival celebrates its fifth anniversary with more than 20 films exploring humanity's role in the natural world. The festival will run from Oct. 12 to Oct. 18 at Cornell University, with additional screenings at Ithaca College and Hobart-William Smith Colleges.

Topics of this year's films include environmentally sustainable planning, citizens' roles in watershed preservation and the little known history of "peaceful" nuclear testing. The controversy surrounding the massive construction of China's Three Gorges Dam, and the decline of two of the American West's most important animal species, the buffalo and the prairie dog, also are examined.

The festival will kick off with a special screening of "The World Changed Today," a documentary about internationally known environmental architect and planner Bill McDonough, two weeks after its world premiere at the Guggenheim Museum.

"We are proud to be showcasing these films," said festival coordinator Christopher Riley. "These works prove that film can be used to express opinions and, maybe, change the world."

All screenings and discussions are open to the public and most are free of charge. The Cornell Environmental Film Festival is presented each year by the Cornell Center for the Environment, the Einaudi Center for International Studies and Cornell Cinema, with support of other units at Cornell and other participating colleges.

More detailed descriptions of the films and a full list of sponsors are available at the web site http://www.cfe.cornell.edu/filmfest/home.html. Included in the fifth annual Cornell Environmental Film Festival are the following:

• "The World Changed Today," Friday, Oct. 12, 7:15 p.m., Willard Straight Theatre, with filmmaker Chris Bedford. World-renowned environmental designer Bill McDonough influences industries from small textile shops to mammoths like Nike and Ford as he strives to help create sustainable businesses. Tickets are $4.50 ($4 for students, seniors and children 12 and under). A reception will follow.

A scene from "In the Light of Reverence," showing Oct. 18.

• Environmental Animation Festival, Saturday, Oct. 13, 2:30 p.m. Willard Straight Theatre, with singer/songwriter Jan Nigro. A collection of funny, touching short films for kids of all ages.
• "The Waterkeepers," Saturday, Oct. 13, 4:30 p.m., Willard Straight Theatre, with representatives of the Finger Lakes Watershed Steward. An inspiring look at some of the successes of the bay-, river- and sound-keepers from Alaska to New Jersey.
• "Endurance: Shackleton's Legendary Antarctic Expedition," Saturday, Oct. 13, 7:15 p.m., Willard Straight Theatre, with Theodore Hullar, a director of Atlantic Philanthropies USA. "Endurance" documents the 1914 voyage of Ernest Shackleton and his crew to Antarctica and their desperate struggle to survive after tragedy strikes and their ship is lost. Tickets are $4.50 ($4 for students, seniors and children 12 and under).
• "Jalamarmaram (The Whisper of Waters)," Sunday, Oct. 14, 4:30 p.m., Willard Straight Theatre, and Tuesday, Oct. 16, 5 p.m., Park Auditorium, Ithaca College, with panel discussion. Politics and fantasy fuse in this tale of an 8-year-old boy, the memory of his dead father who fought a grim battle against the menacing presence of a local factory and a mermaid in a carnival who yearns to be free.
• "Last Year's Rain Fell on Monday," Sunday, Oct. 14, 4:30 p.m., Park Auditorium, Ithaca College, with panel discussion. Filmed in the deserts of Namibia where the temperature goes up to 110 degrees, this film shows the harshness of life in an isolated but magnificent area. 
• "In the Light of Reverence," Sunday, Oct. 14, 7:30 p.m., Uris Auditorium, with producer Malinda Maynor; and Thursday, Oct. 18, 7 p.m., Smith Library Geneva Room, Hobart-William Smith Colleges, with Professor Deborah Tall. A powerful documentary that explores American and American Indian cultures' relationship to nature in three places considered sacred by native peoples: Mount Shasta in California, the Colorado Plateau in the Southwest and Devils Tower in Wyoming. 
• "Nine Days of One Year (Devyat' Dnei Odnogo Goda )," Monday, Oct. 15, 4:30 p.m., Willard Straight Theatre, with John Cloud, Peace Studies. This classic Soviet-era film is part love story, part cautionary tale of the perils of nuclear energy. 
• "Building Heaven, Remembering Earth: Confessions of a Fallen Architect," Monday, Oct. 15, 4 p.m., Park Auditorium, Ithaca College, with IC Professor Tom Shevory. Using digital video to its ultimate technological and aesthetic ability, "Building Heaven" presents a new view on our culture and environment
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  A scene from "The Buffalo War," showing Oct. 15.
• "The Buffalo War," Monday, Oct. 15, 7:30 p.m., Center for Theatre Arts Film Forum, with filmmaker Matthew Testa. The lives of America's last wild buffalo herd are on the line as the concerns of ranchers, environmentalists and Native Americans clash on the prairies of Montana. 
• "Nuclear Dynamite," Tuesday, Oct. 16, 4:30 p.m., Willard Straight Theatre, with a panel including professors Judith Reppy and Peter Stein. An engaging look at the atomic era from a new angle, this documentary examines American and Soviet plans to use nuclear explosives for "geographical engineering" in the post-World War II era and the growing public concern about atomic radiation. 
• "Hybrid," Tuesday, Oct, 16, 7:30 p.m., Center for Theatre Arts Film Forum; and Monday, Oct. 15, 7 p.m. Park Auditorium, Ithaca College; both screenings with filmmaker Montieth McCollum. In a rather unusual form, where animations of crawling and mating corncobs alternate with poetic nature scenes, "Hybrid" tells the story of Milford Beeghly and his extraordinary life dedicated to corn.
• "Great Wall Across the Yangtze," Wednesday, Oct. 17, 4:30 p.m., Willard Straight Theatre, with panel including Adjunct Professor Mark Seldon and graduate student Chad Futrel. The construction of the Three Gorges Dam on the Yangtze River promises economical growth, but also ecological concerns, the evacuation of 2 million people and the loss of many sites of historical and religious importance. 
• Video in the Villages, Wednesday, Oct. 17, 8 p.m., Uris Auditorium, with Professor Terence Turner. Three short films show how the Indian tribes of Brazil are using video technology to record their traditions, communicate with other tribes and become advocates for the rainforest. 
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  A scene from "Great Wall Across the Yangtze," showing Oct. 17.
• "Varmints," Thursday, Oct. 18, 4:30 p.m., Willard Straight Theatre, with Associate Professor David Wolfe. "Varmints" details the conflicting perspectives of farmers, ranchers, environmentalists, varmint hunters and ecologists, to ask the question: Is the prairie dog just an agricultural pest or an essential part of the ecosystem? 
• "Hot Potatoes," Thursday, Oct. 18, 7:30 p.m., Center for Theatre Arts Film Forum, with filmmaker John DeGraaf and Associate Professor Rebecca Nelson. Scientists John Niederhauser Nelson search for a solution to the centuries-old problem and modern concern of potato blight. Directed by DeGraaf.