The construction of the 1,776 mile long Transcontinental Railroad is one of the most impressive civil engineering achievements of the 19th century. Begun in 1863 during the Civil War, its construction required the efforts of thousands of workers who conquered demanding terrain and survived harsh construction and weather conditions. Giroux sheds new light on the civil engineers who designed and constructed that marvel, and commemorates the 150th anniversary of the Golden Spike. On May 10, 1869, it was hammered into place, completing the Transcontinental Railroad, which helped knit together the then recently restored Union from its Atlantic coast to its Pacific coast.