The second is correct if referring to a singular instance of memory. If you were impressed by someone’s ability to remember, that would be singular and again the second form is correct there.

If you were talking about a few memories and you were referring to other memories instead of a specific memory, you would use the plural “what memories!!” ” (for example, when referring to an entire year “1986, ah the memories,? On

a first edition, the first story (I think we in the universe have a memory! “) could be taken as sarcasm, even with the exclamation mark. If you know someone who referred to a memory of something, and you wanted to convey that you don’t remember the occasion they were referring to, you’d be embarrassed. But when the

conversation began, is the thought “What does it mean?”