Severe rendering glitch. Foreground objects are see through.

So everything in the background gets rendered through the foreground object, as if its invisible.
The orange wire frames are in the foreground, and behind them is the landscape, but it shows through.
This happens with everything. it seems the farthest object is rendered over everything, and everything in between is occluded, or something. Reverse occlusion?
Wireframe is essentially the only thing that renders correctly.
I don’t know what I did. I don’t know what to do. Help me.