An extra long closet and the rod, mounted in concrete, keeps falling off.
If you want it to be bomb proof, (and why wouldn't you?)  you could cut two 2x4s to the height of the rod, drill holes near the top of them, run the rod through those holes, and screw the 2x4s into the wall with a few tapcons or other concrete screw.  The 2x4 will carry the weight to the floor, the screws will just hold them in place on the wall.  You'll be able to go pretty heavy.  (The bottom end of the 2x4s will rest on the ground.)