Rome has the catacombs; Paris has its sewers. Now New York will have its own subterranean wonder: a 200-ton mechanical serpent’s head.

It is a gargantuan drill that has been hollowing out tunnels for a train station under Grand Central Terminal. As tall as four men and with the weight of two whales, the so-called cutter head — the spinning, sharp-edged business end of a tunnel boring machine — is usually extracted, dismantled and sold for scrap when the work is done.

But the Spanish contractor overseeing the project is taking a different approach. It believes it can save time and money by simply leaving it behind, dormant and decayed, within the rocky depths of Midtown Manhattan. The drill’s final resting place: 14 stories beneath the well-tended sidewalks of Park Avenue.