Downward facing dog is also known as the Adho Mukha Svanasana pose. This is one of my favourite poses, and one of the most basic and first poses you will learn.
Its also an incredibly relaxing pose and easy for beginners to learn without too much effort. I also love the legs up the wall pose, which is done near the end of the yoga class and is very relaxing.
Random picture of a hydrangea in my Health/Yoga themed post.