With a name meaning cottonwood in Spanish, Alamosa was established in 1878 by the Denver and Rio Grande Railroad, quickly becoming an important Colorado rail center. The commercial center of the San Luis Valley, which is located in south-central Colorado and recognized as the largest intermountain valley in the world, Alamosa draws many visitors with its various museums, festivals and more. Travelers enjoy the many natural attractions that are either in or around the town including the geothermal outdoor public swimming pool, Splashland Hot Springs, the Great Sand Dunes National Park and Preserve, which boasts the tallest sand dunes in North America, the San Luis Lakes State Park and the Rio Grande National Forest. Another interesting destination to take in is the Alamosa Wildlife Refuge, which spans 11,168 acres (4,519 ha) and borders the Rio Grande River. The refuge houses many bird species including the endangered Whooping Crane.