One of the world's most famous highways marks its centennial this year. Known for its neon lights and roadside diners, Route 66 boasts a rich and complicated history that has lured motorists for generations. The 100th anniversary is expected to bring more traffic to the Mother Road as road trippers set out for a slice of nostalgia. The 2,400-mile route stretches from Chicago to the Santa Monica Pier near Los Angeles, tracing paths once used by Native Americans and early pioneers. Hardships and hope are baked into the road's history. It was an escape route for many in the 1930s, a key military supply line during World War II and later a symbol for mobility and freedom.