i lost a hole piece of my scene in the 3D View

i lost a hole piece of my scene in the 3D View
Does someone know how i get my entire scene back to view.

(I was Messing with CTRL + B so i could render just a part of the scene, and then this happend)


You probably used Alt+B by error and enabled the clipping border. Remove withAlt+B (View / Clipping Border)
https://docs.blender.org/manual/en/dev/editors/3dview/navigate/clip.html