If you could receive a post card from any era and place, what would it be about and from who?

For me it would be interesting to get post cards from my grand father who I never met but went to seas before marriage (I guess, I have seen one photo worth of evidence). I have only a handful of photos and everyone who really remembers him has already passed away.

dall-e generated fake, vintage postcard with prompt "Post card, shanghai late 1800's, landscape photo, coffee-stained."