Eurocodes are a way of making sure buildings are built really safely. They are like a set of rules that builders and engineers need to follow when designing a building. The rules are made by a group of smart people all over Europe and they put their heads together to make sure that buildings are strong enough to stand up to things like wind and earthquakes.
These rules are important because buildings need to be strong to protect people inside. For example, if there is a big storm, people need to know that they won't be hurt because the building will keep them safe. The rules also help make sure that buildings don't fall down accidentally. That would be really bad!
So, it's like a big book with lots of rules that all the people who build and design buildings follow to keep everyone safe.