Sunset is the time of day when the sun goes down below the horizon. The sky goes from dark to coloured with lots of shades of pink and orange and red and then to deep purple before the sun goes completely below the horizon and it is night time.
The time just after sunset before it gets completely dark is called dusk. The opposite of sunset is sunrise.
When you go out in the sun, you can get sunburnt. Pale skin is more likely to burn than dark skin. Your skin tries to protect itself from the sun by producing melanin, which makes your skin darker. We call this a suntan. The people in the picture have darker skin where the sun has been shining on their skin, and paler skin where it was protected by their shoes.
Sis forSuperimpose
Superimpose means to place one image over another so that both may be seen, often by altering the size or transparency of one of the images.
