Genesis 6:1-4

More and more people were born, until finally they spread all over the earth. Some of their daughters were so beautiful that supernatural beings came down and married the ones they wanted. Then the LORD said, “I won't let my life-giving breath remain in anyone forever. No one will live for more than 120 years.” The children of the supernatural beings who had married these women became famous heroes and warriors. They were called Nephilim and lived on the earth at that time and even later.