How was life different before the Flood?

Stunning Details from the Bible

•  It had never rained; a mist came out of the ground to water the plants.
• Humans lived nearly 1,000 years. (The Bible doesn’t explain why, it may be that the ocean of water in the heavens somehow protected people.) After the Flood, rain and life expectancy declined within a few generations (see Gen. 11:10-25).We know the length of those pre-Floodyears was the same as our years because genealogies and time lines can be traced through the Old Testament. When Jacob (Israel) and his sons entered Egypt, he told the Pharaoh that he had lived for 130 years, but his fathers had lived much longer (see Gen 47:9) . If you do the math in Gen.11 you'll find that Shem was still alive at that time.
• Many years before the Flood, people already forged weapons and musical instruments from brass and iron (see Gen. 4:21,22).
• Only eight righteous persons were rescued on the ark. Noah, his wife, his three sons and their wives. 
• Noah was 600 year old when his family entered the ark.
• His sons were all in their nineties yet still youthful. We know that because none fathered children until after the Flood. Shem’s first child was born when he was one hundred years old, two years after the Flood. (Since it seems only likely that the only surviving eight people on earth would have wanted to have as many children as quickly as possible to repopulate the earth, Shem and his wife likely suffered infertility as did others later in his direct line, i.e. Abraham and Sarah.)
• The Nephilim (singular Nephal), probably fallen angels, were on the earth in those days. They were supernatural giants who mated with human women and produced what the Bible refers to as “heroes of old”(see Gen 6:1-4) (There are those who hypothesize that stories of Roman and Greek gods and goddesses were based on these fallen creatures.)