A dream is a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep. The content and purpose of dreams are not fully understood, although they have been a topic of scientific, philosophical and religious interest throughout recorded history.
Dreams can be fascinating, exciting, terrifying, or just plain weird. While there is no clear consensus on why we dream, researchers have learned quite a bit about what happens while we are dreaming. Here are 10 things you should know about dreams.