Grand Central Terminal, aka Grand Central Station, in New York was built with lots and lots of granite. Granite is a rock that contains uranium and potassium – both radioactive substances. Due to this fact, Grand Central Terminal (and anything else built with granite really) technically becomes a producer of radiation. The amount of radiation is pretty trivial, but in the case of Grand Central Terminal, it is more than is legally allowable by a nuclear power plant.
Now with that in mind, don’t start thinking that Grand Central Terminal is a radioactive death trap. The amount of radiation that the building puts off is safe. It really says more about the incredibly strict safety requirements of nuclear power plants.