Humans have inhabited this area for nearly 12,000 years. It became a key transportation route for Native Americans, who deemed it neutral territory for all tribes traveling through, and for the Europeans who later came to explore and colonize. The Ohio & Erie Canal, opened in 1827, helped put the Midwest on the commercial map, and the region boomed. By the 1860s, the railroad replaced the canal in importance, but the valley remained a popular green spot for the residents of nearby cities. In 1974, the Cuyahoga Valley was named a National Recreation Area, and in 2000 became a National Park. It is also part of the Ohio & Erie Canal Heritage Corridor.