How did they deliver unguided bombs in the old days?

Ok I know that modern planes have CCIP which is a circle that appears on your HUD that tells you where your bomb would fall if you were to release it now, so you simply position your plane so that the circle is over your target and release your bomb.

Obviously HUDs and computers have not been around forever, so how did they deliver bombs accurately before the invention of the CCIP?

Also, which planes have CCIP? I know all 3rd gen western planes have it (ie F-14/15/16/18, Mk2000). What about earlier western planes, or earlier Russian planes. I’m assuming a Mig-21 wouldn’t have it?