Dream is a word used to describe the subconscious experience of a series of images, sounds, and ideas.
Everyone is thought to dream between 3 and 6 times per night, and each dream lasts between 5-20 minutes.
Dreaming occurs during REM sleep, which makes about 2 hours of our 8-hour sleep.
The remaining 6 hours are of no real use for us.
Another interesting fact about dreaming is that your brain can't come up with entirely new environments and people, so everything seen in dreams must have been seen before in real life.
You need to look at a person for about 30 seconds for your brain to be able to recreate it in dreams.