Broccoli belongs to the cabbage family. What we are actually eating is the flower of the plant.
It originated in the Roman Empire (not quite in the form as we know it).
It can be eaten raw or cooked.
When it comes to cooking, broccoli is highly versatile and can be fried, baked, steamed, pretty much anything. Just be careful not to over cook it, as it looses its colour, texture and flavour.