Gerudo Valley

"My country lay within a vast desert. When the sun rose into the sky, a burning wind punished my lands, searing the world. And when the moon climbed into the dark of night, a frigid gale pierced our homes. No matter when it came, the wind carried the same thing... Death. But the winds that blew across the green fields of Hyrule brought something other than suffering and ruin. I coveted that wind, I suppose..."

- Ganondorf

Gerudo Valley (ゲルドの谷, Gerudo no Tani) lies and is accessible from the far west of  Hyrule Field. The valley is divided by a large chasm at the bottom of which is Zora's River, which leads into Lake Hylia. If Link goes there as child, he can't get to the other side because of the Gerudo blocking the way. He can, however, take a cucco and glide down to a small indent at the bottom of the canyon to find a Gerudo, a cow, and soil for planting magic beans. As an Adult Link, the bridge has been destroyed, and must use the longshot or Epona to get on the other side. Once you rescue all the carpenters, they will repair the bridge.

It is home to the race known as the Gerudo and their fortress. The main antagonist of the games, Ganondorf, was born in this land. As seen in the quote above, the hostility of the valley appeared to be the reason for trying to take over Hyrule, so he could provide a better life for himself and his people. However, the power of the Triforce probably corrupted his mind beyond his original goal.