Who is the best actor in the world?

Could you please elaborate on your criteria for determining the "best actor in the world"? Is it based on their technical skill, versatility, range of roles, box office success, critical acclaim, or a combination of these factors? Who do you believe stands out among the current crop of actors, and why do they deserve this accolade? Also, is it fair to compare actors from different eras and cultures, or should the title be reserved for contemporary figures?