Okay kiddo, so have you ever heard of really big tall mountains that are super hard to climb? Well, one group of those mountains are called the "eight-thousanders". They're called that because they are all over 8,000 meters tall, which is really, really high!
There are 14 of these mountains in the world and they are all located in the Himalayas (a big mountain range in Asia) and the Karakoram (another mountain range in Asia). These mountains are so tall that they are covered in snow and ice all year round, and it's really hard for people to climb them because the air is thin and it's hard to breathe.
Even though these mountains are really difficult to climb, lots of people try to do it every year! They have to be in really good shape and have lots of special equipment like ropes, harnesses, and oxygen tanks to help them breathe. It's a really big accomplishment if someone is able to climb all 14 of the eight-thousanders.
So there you have it kiddo, the eight-thousanders are a group of really big tall mountains that are over 8,000 meters tall and are located in Asia. They're really hard to climb, but lots of people try it anyways!