DANNY: Everybody meets at the clock, you know? Where are you gonna be? Oh, meet me at the clock. RHIANNON: This is a very common phrase among New Yorkers, and everyone knows just which clock you mean – the iconic 4-faced ball clock on top of the information booth. Each 24-inch face is made with opalescent glass, often called opal glass or milk glass. DANNY: Well, you know, time goes synonymous with, with human life, right? So, yeah. Time is a big thing here in the terminal. So the clock on the main concourse has four sides. And this day and age, they all read the same time. But back in the day, each side would have each time zone – Eastern, Pacific, and so on. They all had different times because, if you were traveling on the Hudson line going towards Maryland or out west, and you had a train coming in from the West coast they’d say, yeah, we're gonna be crossing there at three o'clock. That train could be sitting there all day because it's thinking three o'clock this time. That was big, because we had Amtrak that would go out west. You know, this was the hub of the world at one point. MICHAEL: In 1913, when Grand Central Terminal opened, there was a clock master to take care of all the clocks in Grand Central. Now, with modernization, there is less need to look at the clocks, but their beauty survives. Our clock master had a very important position. His work was scrutinized because if the clocks were wrong, people would be late for their trains and their trains would not run on time. The railroad needed accuracy. So the Clock Master was a revered position. Tick Tock was the last clock master of Grand Central Terminal. I had the pleasure of working with him for the last four years of his tenure. He retired in 1984. Here was a clock master who made his own tools. He was responsible for over 400 clocks in the railroad system. His real name was Mr. Paul Kugler, the last clock master of Grand Central Terminal. /He was really a great guy. He wasn't afraid to show you anything. He was really a craftsman. He knew gemology, metalology, horology. Horology is the study of timepieces. He was not afraid to show you anything if he knew you were really interested. Craftsmen like that don't really exist that much today. I learned as much as I could from him and tried to apply it. He would give me projects to do, old clocks to repair, and I still have 'em at home. And they work. RHIANNON: The clock is now set to the United States Naval Observatory's atomic clock, accurate to a billionth of a second – so go ahead, set your watch.