I've found myself in this discussion more than a few times when friends ask "What is the hardest record in sports to break?" Often you will hear some of the more prominent records such as: career wins in baseball (Cy Young - 511) or the longest hitting streak (Dimaggio - 56). There are Herculean mountains to climb in other sports as well ... the highest NBA single season scoring average (Chamberlain - 50.36 ppg) or the most rushing yards in the NFL in a single season (Dickerson - 2,105 ... especially hard in today's NFL where it's running back by committee and a pass happy league to begin with!).
Of all the records in sports, I've come up with two records that most assuredly can NEVER be broken. They are: the most consecutive no-hitters (Vander Meer - 2 ... you would have to throw 3 consecutive no hitters to BREAK the record ... will never happen) and most grand slams in a single inning, off the same pitcher (Tatis - 2 .. so you would have to hit 3 grannies in the SAME inning and off of the SAME pitcher to break it ... never gonna happen!)
So, on a winter night void of football ... what is your vote for unbreakable sports record?