Central Park was first approved in 1853 as a 778-acre (3. 15 km2) park. In 1857, landscape architect Frederick Law Olmsted and architect/landscape designer Calvert Vaux won a design competition to construct the park with a plan they titled the "Greensward Plan". Construction began the same year, and the park's first areas were opened to the public in late 1858. Additional land at the northern end of Central Park was purchased in 1859, and the park was completed in 1876. After a period of decline in the early 20th century, New York City parks commissioner Robert Moses started a program to clean up Central Park. Another decline in the late 20th century spurred the creation of the Central Park Conservancy in 1980, which refurbished many parts of the park during the 1980s and 1990s.