What happens in a "Saturn Return"?

Saturn teaches us lessons through grief and hard work. Every time Saturn moves through a house we learn a lesson pertaining to that house. When Saturn returns to his original place (where he was when you were born) it is called a "Saturn Return". The effect is that you will have learned (or failed to learn) a lesson in each area of life (all 12 houses).

Thus most cultures do not consider someone fully mature and adult until their first Saturn Return, which takes about 27-30 years.