b) Promontory, Utah

The two lines of the first Transcontinental Railroad met at Promontory, Utah, on May 10, 1869. This historic event was marked by the “Golden Spike Ceremony,” where a final golden spike was driven to join the Central Pacific and Union Pacific railroads. The completion of the Transcontinental Railroad revolutionized travel and commerce in the United States by significantly reducing the time and cost of coast-to-coast transportation. It was a monumental achievement in engineering and labor, symbolizing the unification of the nation and the American spirit of innovation and progress.