Sunset

Here’s the science bit:

“Because the sun is low on the horizon, sunlight passes through more air at sunset and sunrise than during the day, when the sun is higher in the sky.  More atmosphere means more molecules to scatter the violet and blue light away from your eyes.  If the path is long enough, all the blue and violet light scatters out of your line of sight.  The other colours continue their way to your eyes.  This is why sunsets are often yellow, orange, and red.”