Just don't call it Grand Central Station.
That's one of the first lessons Daniel Brucker gives when he shows people around New York's transportation masterpiece, Grand Central Terminal. A station, he points out, is a stop along a rail line. But all trains coming into Grand Central end there.
So Grand Central Terminal it is.
The terminal, which opened in 1913 and spans 49 acres in Midtown Manhattan, was designed to celebrate the most modern mode of transportation. Its 67 tracks and 44 platforms carry more than 750,000 people a day.
This is actually the third Grand Central on the site. The original was Grand Central Depot, completed in 1871, and then rebuilt as Grand Central Station in 1899-1900.
Brucker, the manager of Grand Central Tours for Metro-North Railroad, took NBC News behind the scenes to reveal some of the hub's historic secrets — including the world's largest example of Tiffany glass, a private train station customized for Franklin Delano Roosevelt and the story of a shoot-on-sight order during World War II.
All trains in and out of Grand Central are powered by a "third rail," which delivers electricity, generated by massive rotary converters in the deepest basement, 13 stories beneath the tracks.
During World War II, those converters were scouted by Nazi spies as a potential target for sabotage, a plot that could have disrupted much of the movement of troops and material through the Northeast. The plan exploited the converters' weakness: they could be disabled by simply pouring sand into the equipment. Hitler's plan was thwarted in 1944 after his agents were intercepted at baggage claim.
Another secret is the whispering gallery: If two people stand in the diagonal corners of the square foyer in front the Grand Central Oyster Bar, and speak softly, their voices carry across the arched ceiling.