Professional production values make us believe data presented to us in maps, charts and graphics. But consider 'Everyone Ever in the World'. Clever, artistic, beautifully clear and without any sort of basis in fact. Here's Steven Pinker to explain why (worth watching in full but for those of you in a rush, speed to 4.00 mins in) :
What went wrong: If you're interested in why they got it wrong, they didn't take into account 'missing data'. We know how many people died in WWII and it's true we have only a few records of the people who were murdered in 2000-1000 BC but that doesn't mean it was a peaceful time, its just the record keeping was dire compared to today.