Rolling tallgrass prairies once stretched for miles across Illinois, covering millions of acres with a land of sun, wind, and open horizons. Their grasses grew six feet or more by late summer, and wildflowers bloomed at different times through the growing season, creating a constantly changing, multi-colored panorama. Herds of bison, elk, and other wildlife once lived here in numbers that amazed early explorers. In summer, insects filled the prairies with sound while birds moved among the grasses feeding on them, and red-tailed hawks watched from above for small rodents or snakes in the dense grass. In winter, life retreated underground, sheltered by dry, matted grasses until spring warmth returned.