surprise. Ezekiel sees a canoeist heading for whitewater at Horseshoe Falls and warns him ashore before he reaches the rapid. The film then chronicles the history of aviation, beginning with hot-air balloons. The dawn of aviation is described as "like the opening of a new eye", allowing humans to reach untouched places and extend human limits. The desire to fly also inspired the creation of skyscrapers. Although hot-air balloons were revolutionary, the majority of Americans still used horses; faster trains were invented, then cars and mechanical aircraft. The Roaring Twenties saw the invention of barnstorming, expanding access to aviation among Americans. Military aviation formed flight demonstration squadrons like the Blue Angels. With airlines, flying became a common mode of travel and access to the American territory expanded westward beyond the contiguous United States. After wide-body aircraft, ultralight aviation was invented. To Fly! ends with the launch of the Saturn IB rocket as part of the Apollo–Soyuz mission, at the Kennedy Space Center on July 15, 1975. After dubbing spaceflight a historical feat, the narrator suggests it can be used to discover extraterrestrial life, and uses it to describe human imagination as limitless, which is credited to the philosophical awakening caused by the vertical view of the world. The film ends with a view of Earth, and the narration: We have come a long way from a time when people gazed enviously upon the birds in-flight. Today, we look upon our planet from afar, and feel a new tenderness for the tiny and fragile Earth. For we know now, that even as we walk upon the ground, we are ever in-flight through the universe. And so, we begin to realize that human destiny has ever been, and always must be, to fly! Production Background The 1960s and 1970s saw increasing numbers of museum theaters as part of the effort to modernize museums with audiovisual content. The idea of a giant-screen theater at the National Air and Space Museum (NASM) was mooted in 1970 in a 153-page report by the National Museum of Natural History (NMNH) curator team, which argues the NASM needs a "contemporary medium of communications" that will resonate intellectually and psychologically. The report suggested a giant-screen experiential film that would showcase the American landscape and the country's introduction to technology, ending with predictions of the country's future. Among these giant-screen film formats was IMAX, characterized by its tall screen