Source : Webster's Revised Unabridged Dictionary (1913)

Cleopatra's needle \Cle`o*pa"tra's nee"dle\ [So named after
   Cleopatra, queen of Egypt.]
   Either of two obelisks which were moved in ancient times from
   Heliopolis to Alexandria, one of which is now on the Thames
   Embankment in London, and the other in Central Park, in the
   City of New York.

   Note: Some writers consider that only the obelisk now in
         Central Park is properly called Cleopatra's needle.