First 3D shooters

Do you remember times when Pentium or Celeron "was inside"? I think first 3D shooters appeared then, for example classic Wolfenstein 3D, Doom or Duke Nukem. Those games was played by all young computer owners. Objectives was understandable and clear, it was necessary to survive and kill as many enemies as possible. Only few weapons, really poor graphics, and not surprising music. Today we can say those games were boring, but it was enough to have a great time. Do you remember those days? Bring that atmosphere back and download old 3D shooters here.