The 2km long Coaling Tunnel was built between 1921-24, when Taiwan was still under Japanese occupation. Designed to connect north-south traffic on the island, it was a major thoroughfare until it closed in 1968, when a new road meant it became little used. It reopened in 2008 as a bicycle route that promotes the growth of sustainable tourism. As you exit the tunnel you can join a bicycle path that tours through fishing villages and coastal scenery on a 20km round trip. Since 2008, 1.85 million people have visited the tunnel, bringing almost NT$300 million in benefits to the local economy each year.