Mayor Mike Bloomberg told the crowd, "It's a symbol of all that is great about our city. It's rooted in an incredible history while also being thoroughly modern. It represents beauty and art, but also commerce and industry.
"It's an innovative and visionary place, and it has the same power to inspire awe and wisdom whether you walk these corridors every day or you're visiting here for the first time."
In his speech he referenced Jacqueline Kennedy Onassis, the former first lady, who led a campaign in the 1970s to preserve the building that was in danger of being razed for hotel development.
Onassis's daughter, Caroline Kennedy, was present at the centennial celebration and spoke of her mother's efforts to save the architectural masterpiece. "As a native New Yorker, she cared deeply about this city. She was so upset when Penn Station was torn down, the Metropolitan Opera house, and when it came to Grand Central it was just too much. She cared about its neighborhoods, its families, its artists, its dreamers."
Grand Central Terminal under construction in 1912. The iconic rail hub turns 100 years old this month.
The terminal which has been the background of dozens of Hollywood movies and television shows throughout the years, brought out several celebrities, including former Mets star Keith Hernandez and Grammy award singer Melissa Manchester to speak and perform.
Actress Cynthia Nixon of "Sex and the City" fame, said "Grand Central is everything that New York is. It's big, its loud, its functional, its dysfunctional, it's crowded, it's noisy but it is something that New York is too that we sometimes forget: It is so beautiful."
As the formal program for the celebrations wrapped up, a cake in the form of the terminal's clock was rolled out and the entire grand hall of people sang "Happy Birthday."