Sichuan Basin
Highway construction within Sichuan Basin intensified in the 21st century. Expressways through the basin include the G5, G42, G50, G65, G75, G76, G85, and G93. All expressways that connect the Sichuan Basin with other parts of China have been designed to utilize a series of tunnels and bridges to cross the mountainous surrounding terrain. Notable examples include the long Zhongnanshan Tunnel through the Qin Mountains to the north and the high Sidu River Bridge through the Wu Mountains to the east.