N1-L3
The N1-L3 was a Soviet super heavy lift vehicle, its first stage (as of writing this) is the most powerful ever flown.
The N1 was intended to be the rocket to put a Russian cosmonaut on the moon before the Americans, but you probably know it for causing the biggest none nuclear man made explosion ever. The Soviet engineers had been tasked to put a man on the moon with an 8th of the budget that NASA had, and so they had to compromise a lot. The most obvious one being the amount of engines, unlike the NASA engineers the soviets couldn't find a way to stop the combustion instability that a large engine-bell causes. And so the decision was made to use lots of smaller engines on the N1, which is what made it so powerful, but it was also its biggest flaw. testing so many engines at once was near impossible and very expensive, so only a 3rd of all engines were tested at the same time, which wouldn't give the correct results and the plumbing on the N1 was very very complex.
The N1 would fly 4 times, all times ending in a huge explosion. The most famous being that biggest man made none nuclear one. It happened when every engine except one shut down at the same time due to faulty AI. After the 4th launch of the N1 in 1972 the USSR had 2 flight ready N1 but the decision was made to scrap them, they had lost the race to the moon years ago and the public interest in space was falling rapidly. many belive that if they had flow the remaining N1's they might have worked, since at that point pretty much all flaws had been iron out. But no one can't say for certain. The N1 never once made it to stage sepuration, it possible ironing out the flaws in the other stages would have been just as time consuming and costly. and with the scraping of the N1, the Russian dream of puting a man on the moon died. But if they had pushed on and landed on the moon, that might have worried the americans, which might have breathed new life into the space race.
About Replica
My N1 replica you see is of the 4th and final N1 that flew. its about 2/3rds (66%) the real size of the real rocket. It is over 1.6k parts and contains the LK lander and Soyuz-LOK within its fairing. The game drops FPS a fair bit, especally when staging, but it gets better and better as more and more of the rocket drops off. but even with a decent PC expect 1 trip to the Mun and back to be about 40 min long. despite how complext it it it flies pretty well, but the roll is a bit janky for the 2nd and 3rd stage. it has just enough fuel in the 4th stage to circlerise around Kerbin and get to the Mun. Landing on the mun is pretty easy, same with getting back into orbit. just like IRL the docking mechanism can't transfer a crewmate. In the LK the is a chair that a Kerbal can sit in, and its close enough to the edge that they can get in and out without issue.
https://kerbalx.com/BullShootLatinName/N1-L3_2
link to the replica + more photos