Draining the Everglades was first suggested in 1848, but was not attempted until 1882. Canals were constructed throughout the first half of the 20th century, and spurred the South Florida economy, prompting land development. However, problems with canals and floods caused by hurricanes forced engineers to rethink their drainage plans. In 1947, Congress formed the Central and Southern Florida Flood Control Project, which built 1,400 miles (2,300 km) of canals, levees, and water control devices. The South Florida metropolitan area grew substantially at this time and Everglades water was diverted to cities. Portions of the Everglades were transformed into farmland, where the primary crop was sugarcane. Approximately 50 percent of the original Everglades has been turned into agricultural or urban areas. When the construction of a large airport was proposed 6 miles (9.7 km) north of Everglades National Park, an environmental study predicted it would destroy the South Florida ecosystem. Restoring the Everglades then became a priority.
National and international attention turned to the environment in the 1970s, and UNESCO and the Ramsar Convention designated the Everglades as one of only three wetland areas of global importance. Restoration began in the 1980s with the removal of a canal that straightened the Kissimmee River. The water quality of Lake Okeechobee, a water source for South Florida, became a significant concern. The deterioration of the environment was also linked to the diminishing quality of life in South Florida's urban areas. In 2000, a plan to restore the Everglades was approved by Congress; to date, it is the most expensive and comprehensive environmental repair attempt in history. The Comprehensive Everglades Restoration Plan was signed into law, but the same divisive politics that had affected the region for the previous 50 years have compromised the plan.