This large, lush green valley is surrounded by towering, rocky cliffs on either side. A fast-moving river runs through the center of the valley, flanked by trees and plants with their leaves swaying in the breeze. The sky is a lovely, bright blue, and mountains can be seen in the far distance. To bring this image to life, I would use bold, vibrant colors for the river and cliffs, such as deep blues for the river and grays for the cliffs. I would then use lighter pastel shades of greens, blues and browns for the trees and plants to create a soft and inviting atmosphere. For the sky, use a light shade of blue, with darker deeper blues to fill in the mountains as well as to add a sense of depth. Finally, I would use a gentle shade of pink or orange to set the sun in the sky.