actually ravana's lanka is not srilanka but australia. the stone bridge which was shown by NASA doesnot end in srilanka but simply bypasses it and proceeds towards australia. no ramayanic evidence has been found in srilanka but an ancient palace has been found in eastern australia. the maori tribesmen in australia belive in ravan as their god and have local customs similiar to the ramayanic period. more research needs to be done on it.