Question: after the flood, where in the Bible did the black race start from

The Bible tells us that Adam knew his wife, Cain knew his wife, Abraham knew his wife, Isaac knew his wife etcetera, etcetera.

It didn’t tell us if they were black or white.

Lets forget everything before the flood for 1–sec.

My question is: after the flood, where did the black race start from? how did it happen – the birth of the first black man? except ofcourse Noah and his family were all black.

 

p.s: the above is just my thoughts running, nothing special.