Most scientists believe that birds evolved from small therapod dinosaurs. The key step was the development of feathers, turning animals that could walk or climb into animals that could fly. The first fossil discovered with feathers was found in 1861; just two years after Charles Darwin published his theory of evolution in 1859. This fossil is known as archaeopteryx and is the earliest bird known to science. Archaeopteryx, which lived over 150 million years ago, is a classic example of an evolutionary link between two groups of animals. As of today, there are only ten known specimens of archaeopteryx. This premier exhibition presented some of the finest known fossils from the late Jurassic period showing life at the time of these first birds. Fossils from the world renowned quarries of Solenhofen, Germany were featured. "Archaeopteryx: Icon Of Evolution" was organized by the Houston Museum of Natural Science.