[CentOS] What happened to the /lib64 & /usr/lib64 on x86_64 its there when I install RedHat x86_64?

Fri Aug 4 00:21:48 UTC 2006
Don Hudson <donh1964 at usnetworx.net>

Hi,
For some reason I'm really confused over 64bit RedHat vs Centos.
On RedHat install of 64bit I have a /lib64 and /usr/lib64 along with the 
/lib and /usr/lib but when I did a full install of Centos 64bit I only 
wound up with /lib and /usr/lib.
Did I miss something or what?
Will both 32bit and 64bit software work?
Thanks,
Don