Charting the race between the Union Pacific and Central Pacific to construct a transcontinental railroad to link the U.S. It ended May 10, 1869, in Promontory Point, Utah. The construction was "the engineering marvel of the 19th century -- and a flat-out swindle,” says narrator Michael Murphy. It was also "the technological manifestation of Manifest Destiny,” says historian Wendell Huffman, one of the program's commentators. And it sealed the fate of the Plains Indians. When the final spike was in place, Murphy says, "America could take its place as the first nation in the world."