When was the tower of Babel relative to the flood and Abraham?
The tower of Babel came about halfway between the flood and Abraham. Since the flood was roughly 400 years before Abraham, Babel occurred approximately 200 years after the flood and 200 years before Abraham, using round figures. This places it in the middle of that 400-year span.
Les explains from the timeline that Abram, later Abraham, appears about halfway between Adam and the cross, with roughly 2000 years on each side. He then places the flood about 400 years before Abraham came on the scene, and the tower of Babel about halfway in between that, meaning about halfway between the flood and Abraham. These are round figures. In the surrounding context, Les notes that after 2000 years of human failure, God begins something different, leading to Abraham.