The World's Most Populous Countries

A bar graph compares quantities by height. Anyone could read from the table that China has 1,369 million people and the United States 321 million, but the bars make the ratio obvious at a glance: the two tallest tower over the rest, and everything from the third country down sits in a band of roughly similar size.

That is what bar graphs are for. They are better than a pie graph when the point is comparison rather than shares of a whole, and better than a line graph when the categories are not ordered in time. The slider trims the list to the leading few countries, which changes the vertical scale and so changes how large the remaining differences look.