Does that include every single mum and dad of every mum and dad. If you just follow your direct paternal or maternal line it's a lot easier but a very tiny sample.
If I go back to 1900 I have Polish Jews, Panamanian Jews, Dutch Jews, Irish Jamaican, Irish, West Country, Essex and East London.
I have discovered ancestors in 1460s Buckinghamshire, which was a surprise as my Mum's maiden name is Deverell and we assumed they were Huegenot as they came from Whitechapel. Turns out it was Norman in origin. Apparently Ian Duncan Smith's wife swindled the family title from an ancestor...