Why does the Atlantic Ocean have the world’s largest drainage area?

The Atlantic Ocean possesses the world’s largest drainage area primarily because the continents bordering it—North America, South America, Europe, and Africa—tend to slope toward the ocean basin.1

This geographical orientation causes the Atlantic to receive the waters from a significant proportion of the world’s major rivers. These include, among others, the Amazon, Mississippi, Congo, Niger, Orinoco, and St. Lawrence rivers, as well as those draining into the Mediterranean, Black, and Baltic seas.1