digital illustration of the river tethys flowing through an alien landscape, art by Benoit B. Mandelbrot, Steven Belledin, Martin Johnson Heade, Lee Madgwick, and Caspar David Friedrich, a beautifully terraformed alien planet, wide angle, panoramic, fantasy, 8k resolution, deviantart, trending on Artstation, concept art, digital illustration, HDR, Octane, National Geographic Photo