Sandiaojiao (San Diego) is the cape in the northeast of Taiwan and the easternmost point of the island. In the past, the Xueshan Range extending westward from Sandiaojiao (San Diego) were an obstacle to travel between Taipei and Yilan. The earlier inhabitants used the Danlan Trail system to travel between the two until the Caoling Tunnel was established in 1924. Since railway transportation began and the tunnel built that year was replaced by new tunnels later, the old tunnel became part of the Old Caoling ring road of bicycle path. With the old tunnels in series, you can ride around Sandiaojiao (San Diego) and learn about the evolution of northern Taiwan in the process of riding the wind. Additionally, because most of this route is dedicated to cyclists, you can fully enjoy the coastal scenery of the northeast corner, so it is very suitable for most riders. This tour starts from the Fulong Station of the Taiwan Railway in New Taipei City. Follow the signs to the Old Caoling Tunnel, and cross the tunnel to Shicheng inYilan County to the sound of the Taiwanese folk song "Clinking Coins". Cycling along the coastal road, you can enjoy the beautiful sea and the special Lailai geological landscape while cycling and going around Sandiaojiao (San Diego) in the extreme east of Taiwan. When you come to Sandiaojiao (San Diego), you can walk up to the Sandiaojiao (San Diego) Lighthouse, or you can continue to go around the Magang Fishing Port, which is the easternmost fishing port of Taiwan, as well as the Maoao Fishing Port and the Fulong Fishing Port. In the bays and alleys, enjoy the leisurely ride in the northeastern corner. Finally, return to Fulong Station to taste the traditional railway bento (lunch/dinner box), which is the best ending for this small trip.