If you know where you were born you should be able to go to the authorities in that locality and ask your way through the system with the aim of getting a birth certificate. From there you should (I imagine) be able to obtain a Social Security Number and from that would follow the process of getting other documentation right up to a passport whereby you can go anywhere a USA passport is accepted worldwide. Best of luck. Actually, your parents should be able to assist you, unless you are not involving them in this matter.