Where is Nirvana?

If you ask someone that Where is  Nirvana? well~ if you ask him/her about where does the Nirvana exist and you are doing a mistakes because when we talk about Nirvana. its very hard to explain even the meaning of the term Nirvana and its more to talk about where does the Nirvana exist. Nirvana or Nirvana is not something that could be spoken or talked about or could be given definition. It mentioned that Nirvana or Nirvana could be experienced only by Arahants or Buddhas because Nirvana is some kinds of states that could not be able to said by any ordinary person. Once a man asked one scholar " where does the Nirvana exits and how far is it?"  The prominent Buddhist Scholar replied that Nirvana could be climbed by the stairs or steps. that was a joke for the persons who did not answer the meaning of the term Nirvana.