Woah there, dude. The Spinx is in both Greek AND Egyptian Mythology. Remember the friggin' huge statue in Egypt? Yeah, the Sphinx of Giza staring at the constallation of Leo.
Sphinxes are in more mythologies too. In India they have them and Egypt has more variaty like the Cryosphinx, a lion with a Ram's head.
Now, asking questions to a Sphinx is the most noted Greek myth. But if you could ask one, why not ask another?
Edit: You're not going to tell me that Dragons are only in British legends, do you?