Related to the future time travel. You somehow get thrown into the past, say 100-150 years. How do you put out a message proving you're from the future and requesting time travelers to come back and rescue you?

My proposal is to take out classified ads in newspapers, couching it as a code or puzzle to be solved, and put in dates of major future events you know about. D-day, Kennedy assassination, Challenger explosion, 9/11. Top it off with Murder Hornets and they'll know about when you came from.