What is the strongest beer in the world?

Answer 1

Given that cider is made from apple juice which has a natural limit of the amount of sugar it contains and that you can't keep adding sugar to it like you can with beer, the limit of alcohol of a "real" cider is under 9% abv

Answer 2

Utopias from the Boston Beer Company has up to 27% alcohol by volume (ABV) making it the stronges beer in the world.