Okay kiddo, so a long time ago, there was a big ship called Mars. It belonged to Sweden, which is a country in Europe. The ship was a warship, which means it was used for fighting in battles.
One day, the ship was sailing in the sea when it got into a battle with some other ships. The fight was really intense and a lot of cannons were fired. Unfortunately, the Mars ship got hit by a lot of those cannons and it started to sink.
The people who were on the ship tried to save themselves but it was really hard because the ship was sinking so fast. They had to abandon the ship and jump into the sea. Some of them managed to swim to safety, but sadly, a lot of people didn't make it.
After that, the ship sunk to the bottom of the sea and it stayed there for many years. But some people wanted to find the ship and see what it looked like now. So they used special equipment to search for it and they finally found it!
Now, the ship is really old and parts of it are broken, but people are still able to see it and learn about what happened that day. It's a reminder of the brave people who fought in battles and the dangers they faced.