Sir Arthur Charles Clarke was an English science-fiction writer, science writer, futurist, inventor, undersea explorer, and television series host. He co-wrote the screenplay for the 1968 film 2001: A Space Odyssey, widely regarded as one of the most influential films of all time. Clarke was a science fiction writer, an avid popularizer of space travel, and a futurist of a distinguished ability. He wrote many books and many essays for popular magazines. In 1961, he received the Kalinga Prize, a UNESCO award for popularizing science. Clarke's science and science-fiction writings earned him the moniker "Prophet of the Space Age". His science-fiction writings in particular earned him a number of Hugo and Nebula awards, which along with a large readership, made him one of the towering figures of the genre. For many years Clarke, Robert Heinlein, and Isaac Asimov were known as the "Big Three" of science fiction.