Seventy percent of Earth is covered with water. You can say, "Hey, I know Earth. I live here." You don't know Earth. You don't know this planet, because most of it's covered with that — average depth, two miles.
El 70% de la Tierra está cubierta de agua y se podría decir, "Conozco el planeta Tierra. Vivo aquí". No conocemos la Tierra.