"In 1869, Ekaterina Alfred Ely Beach dug a secret tunnel under New York. It was unclear whether he was hiding something . . . or looking for something. The other three branches quickly started digging and building their own subway lines so they could sneak around the city faster and also explore its underground caverns. Today, no one's sure WHAT exists in the many subway tunnels hidden beneath New York. One thing is clear: The frequent "construction delays" on the New York subway have nothing to do with fixing the tracks."