Enoch, son of Cain
After going out from the Lord's presence, Cain moved to the land of Nod, east of Eden. Interestingly, Nod means "wandering", but Cain didn't do anything of the sort. Rather, he settled down in Nod where he fathered a son.
Cain lay with his wife, and she became pregnant and gave birth to Enoch.
It is a fascinating fact about the development of human civilization is that it grew, not from Abel, the shepherd, but from Cain the murderer. After the birth of his son, Cain built a city, the first in the world, and he named this after his first born. It is quite possible that Cain built this city as a gesture of a fixed separation from God.
Cain was then building a city, and he named it after his son Enoch.
Unfortunately, nothing else is known about the city. But we know the line of Enoch continued, and with it, the development of civilization.
To Enoch was born Irad, and Irad was the father of Mehujael, and Mehujael was the father of Methushael, and Methushael was the father of Lamech. Lamech married two women, one named Adah and the other Zillah. Adah gave birth to Jabal; he was the father of those who live in tents and raise livestock. His brother's name was Jubal; he was the father of all who play the harp and flute. Zillah also had a son, Tubal-Cain, who forged all kinds of tools out of bronze and iron. Tubal-Cain's sister was Naamah. (Genesis 4:18-22)