By the time we get to the story of Noah and the Great Flood, sin had infected the entire human race in only a few generations. 

When the LORD saw how great the wickedness of human beings was on earth, and how every desire that their heart conceived was always nothing but evil, the LORD regretted making human beings on the earth, and his heart was grieved.

Genesis 6:5-6

Scripture makes it clear that two lines of descendants emerge out of the story of Cain and Abel: one from Cain, which is given over to sin and wickedness, and one from Adam and Eve’s other son, Seth, who remained faithful to God and, as Scripture describes, “began to invoke the Lord by name” (Genesis 4:26). The descendants of Cain are described like this and this passage describes many the basic elements of human civilization.

Cain... with his wife, ... [ had] Enoch. Cain also became the founder of a city, which he named after his son Enoch. To Enoch was born Irad, and Irad became the father of Mehujael; Mehujael became the father of Methusael, and Methusael became the father of Lamech. Lamech took two wives; the name of the first was Adah, and the name of the second Zillah. Adah gave birth to Jabal, who became the ancestor of those who dwell in tents and keep livestock. His brother’s name was Jubal, who became the ancestor of all who play the lyre and the reed pipe. Zillah, on her part, gave birth to Tubalcain, the ancestor of all who forge instruments of bronze and iron. The sister of Tubalcain was Naamah.

Genesis 4:17-22