Brotherhood Versus GDIEdit
Nod and GDI at the beginning of the incursion fight each other inside Area 51. GDI was attempting to get some flight suits into a vault. This then turned like Time Travel along with Red Alert 1, Generals and Red Alert 2 into some of the timelines. It was an attempt to change time at the height of wars in the Command & Conquer series into their original timelines.
The Area 51 building appears in both Command & Conquer: Incursion and Command & Conquer: Continuum.