WHAT’S WRONG WITH THIS DRAWING?

I took this drawing from a website showing you how to draw perspective. I was shocked to see just what is shown on the internet so I had to ask for your help to see if you can spot the problem. I know the problem, I saw it straight away, most people never see these problems unless they know perspective drawing.

Go to any Art Gallery and look at amazing artwork, some selling at huge prices yet are drawn incorrectly, but do you know what and where it’s wrong?

Tell me what’s wrong and I will let you know if you are right. The clue is the circles drawn at the bottom.