A century ago, rail travel was at its peak in the U.S., and New York City built the massive Grand Central Terminal to accommodate the growth. Built over 10 years, gradually replacing its predecessor named Grand Central Station, the Grand Central Terminal building officially opened on February 2, 1913. The terminal and the surrounding neighborhood thrived -- by 1947, 65 million people a year were traveling through the building. However, in the latter half of the 20th century, rail travel declined sharply, and Grand Central Terminal fell into disrepair, threatened several times with demolition. The Metropolitan Transportation Authority was able to undertake a huge restoration in the 1990s, and Grand Central remains a New York City icon today, 100 years after it first opened.