1957 The world′s longest suspension bridge, the Mackinac Straits Bridge was opened for traffic. The bridge cost an estimated $100 000 000.
1957 The world′s longest suspension bridge, the Mackinac Straits Bridge was opened for traffic. The bridge cost an estimated $100 000 000.
世界上最长的吊桥-美国麦基诺海峡大桥通车。该桥耗资估计1亿美元。