Unity2d Every object is invisible

Question

So I was working on my first project on Unity2d and after like 7 hours of progress, I had a big problem. Every object (Characters, Background, Ennemies) were invisible. I know they are still there because if I select them, their box collider show up. Unfortunately, I didn't find any answer so I hope you got one...

Answer 1

2D games only use the X and Y axis.

Your Z axis is in the negatives and its behind the scene.

Answer 2

Make sure there is a Sprite renderer enabled and attatched to the objects.