Did you know that your chances of developing a kidney stone in your lifetime are 1 in 10? In 1995, more than 3 million people in the United States had some type of kidney condition such as an infection, kidney stones or cancer. More than 300,000 people suffer from renal failure each year and undergo dialysis or await a kidney transplant.

But what do your kidneys do? Why are they so important? Don't they just produce urine? In this edition of How Stuff Works, we will take a close look at our kidneys and find out exactly what they do.