Okay, we admit it, we're biased, but we just LOVE vaginas! Seriously though, the vagina is capable of truly amazing things. It's like the transformer of the human body, growing up to 200% in size when excited (called tenting). Typical vaginas range in size from 2.5 to 5 inches when at rest, but the Rugae allow them to stretch and then shrink back dramatically. Sex cannot stretch out a vagina permanently!
Vaginas are also self-cleaning! They are slightly acidic, and contain a balance of good bacteria, so douching the vaginal canal is not neccesary (or healthy). All in all, the vaginal canal is pretty special.
The Vaginal Canal
Vaginal Opening
Cervix
The "neck" of the uterus which hangs down into the vagina. Anything that passes in and out of the uterus goes through here.
Vaginal Rugae
The most sensitive, and ridged part of the vagina.
These little folds are the key to vaginal expansion and contraction. They stretch out to increase the length and width of the vagina during arousal an childbirth.