Olympic records aren’t always about an individual event performance. One record that seems pretty impossible to beat is most gold medals won by an individual, which swimmer Michael Phelps set in 2016 when he won his 23rd gold at the Rio Olympics. Phelps has 28 medals overall, which puts him comfortably in first place as the athlete with the most medals. Considering that no other athlete has dominated their sport quite like Phelps did—he took gold in more than 80 percent of the events he competed in—this is a record that’s likely to stand more or less forever.

To put it in perspective, before Phelps the record holder for most medals overall was Larisa Latynina, a Soviet gymnast who won 18 medals between 1956 and 1964. That’s a lot of medals, but only nine of them were gold. To put it further in perspective, according to Sportshubnet Phelps has more Olympic gold medals than most countries. To make it all even more impressive, according to NBC sports during his epic run Phelps also set a record for most gold medals won at a single Olympics, with eight in Beijing in 2008. Let’s just say that Michael Phelps will no doubt be remembered as one of the greatest Olympians of all time and leave it at that.

Most Olympic records are technically breakable even if they seem out of reach. Someone could run faster, or win more medals, or score more points. Which makes Nadia Comaneci’s performance at the 1976 Olympics in Montreal one of the most remarkable records ever set, because it can literally never be broken.

That’s because, as reported by AP News, Comaneci’s performance that year was literally perfect. She was the first gymnast to ever score a perfect 10 at the Olympics. It was so unexpected the scoreboards initially displayed 1.00 across the board because they had not been programmed to accept 10 as input.

There are two reasons Comaneci’s record will never be broken. For one, it’s perfection, so it can literally only be matched (and it has, several times according to The Medal Count—by a lot of people, including Mary Lou Retton), and that still leaves Comaneci as the first to do it. For another, as reported by The Mercury News, the International Gymnastics Federation changed its scoring system back in 2006. There can never be another Perfect 10, because gymnastics aren’t scored that way anymore. That’s why you haven’t heard about Simone Biles scoring a Perfect 10—because she almost certainly would have, under the old system.

The United States has done pretty well over the course of the Olympics’ 125-year modern history. As SBNation reports, the U.S. became the first country to win 1,000 gold medals back in 2016 at the Summer Games in Rio—but its domination is even more intense than that. Statista tells us that the USA currently has a total of 2,522 medals overall—almost 1,000 medals ahead of their nearest competition, the combined Soviet Union and Russian Federation.

While that’s an impressive lead, you can’t say the record will never be broken. The USA could enter a steep athletic decline (or cease to be a country), or another country could simply go on a tear. It might take another 125 years, but it’s not impossible.

What would be virtually impossible is breaking the United States’ record of winning 239 medals in a single Olympics, which Guinness World Records tells us they accomplished in 1904 (there’s some debate over which events were officially Olympian, so some sources list 248 medals). The United States was so dominant in St. Louis that year they won more than 85 percent of all the available medals. Factors that fed into the achievement include the low number of participating countries: Olympedia tells us only 10 countries competed. In today’s more crowded and competitive field, it’s doubtful any country breaks this one.

As things stand today, South Korea’s Kwon Jongryul and the Philippines’ Arianne Cerdena are the greatest Olympic bowlers of all time. And they are likely to retain that status forever, for the simple reason that it is very unlikely bowling will ever return to the Olympics.

As reported by FloBowling, fans of the sport have been trying to get bowling added to the Olympic program for years without success. The problem is almost certainly one of popularity: While bowling is a popular casual pastime for many, it doesn’t have a huge following, especially among younger fans the Olympics is desperate to attract.

In fact, bowling has had only one shot: As Fox Sports notes, bowling was part of the Olympic games in Seoul, South Korea in 1988. As Topend Sports explains, bowling was a non-medal “demonstration sport” that year, so Kwon and Cerdena, who placed first among men and women respectively, didn’t get gold medals for their performances. But they do get to hold the records for best bowling performance at the Olympics, and since no one seems to be in a rush to bring bowling back, those records are pretty solid.

When Kevin Young arrived in Barcelona in 1992 to compete in the 400 metre hurdles event, no one had ever managed to break the 47 second barrier. But as NBC Sports reports, Young had an excellent sub-47 second run on the practice track, so he knew it was possible. Sure enough, when he competed in the real thing, he blew everyone away and notched an all-time Olympic and World record of 46.78 seconds.

Twenty-nine years later, the record still stands—in fact, it’s a double record of sorts. As noted by World Athletics, it’s the oldest existing track and field world record. While this record may appear to be in jeopardy—Barron’s notes that Karsten Warholm shattered Young’s world record when he ran a 46.70 in Oslo in 2021, and other runners like Abderrahman Samba and Rai Benjamin have both logged runs under 47 seconds in their careers (Samba has actually broken the 47 second mark nine times), there’s no guarantee any of them will be able to replicate their performances while actually competing at the Olympics.

Young believes that someone will break his record. But as of this writing Young’s record still stands—and it’s possible it always will.