This document provides information on various tunnels around the world, including: - The longest subsea tunnel in China is the Jiaozhouwan Subsea Tunnel which is 7.8km long with 3.95km under the sea. - The English Channel Tunnel between France and UK is the longest undersea tunnel for road vehicles at 50.5km long. - The Delaware Aqueduct in New York is the world's longest continuous underground tunnel at 137km long. - China has built over 10,000 tunnels with a total length of around 7,000km, making it the country with the most tunnels.