World Rivers Day, recognized on the fourth Saturday of every September (this year it falls on Sept. 29), is meant to remind us how waterways impact our lives, and, in the words of the organizers, “[encourage] the improved stewardship of all rivers around the world.”
The story of human culture is intertwined with the history of rivers: Many of the world’s great civilizations were born in the cradle of important river valleys like the Nile, the Tigris and Euphrates, and the Po and Tigris, which provided water, food, and movement of people and goods.
These images from space show how the world’s rivers are both wild, delicate environments and vital arteries for human civilization around the world.