What happens on this planet?

I don´t understand humans. They do strange things.
 For example, many days they go into a building with artifacts in their shoulders when they hear a strange noise.They have different sizes, color, features on the face and eyes.
Inside the building there are different places where they are sitting and whatching other human who is different from them.
These spaces have crosses on the walls and a large green square where there are strange symbols.
It is very difficult to understand this kind because they do strange things in their life I think I'll have to see more.