Did the Giants exist?
They are written of in the bible, history, and archeology
As you can see, Cain is six feet taller than the dump truck

Psalm 37:14-20King James Version (KJV)
14 The wicked have drawn out the sword, and have bent their bow, to cast down the poor and needy, and to slay such as be of upright conversation.
15 Their sword shall enter into their own heart, and their bows shall be broken.
16 A little that a righteous man hath is better than the riches of many wicked.
17 For the arms of the wicked shall be broken: but the LORD...