View full lesson: http://ed.ted.com/lessons/how-menstruation-works-emma-bryce

Made in partnership with the Always #LikeAGirl campaign.

At this moment, three hundred million women across the planet are experiencing the same thing: a period. The monthly menstrual cycle that gives rise to the period is a reality that most women on Earth will go through in their lives. But why is this cycle so universal? And what makes it a cycle in the first place? Emma Bryce gives a primer on periods.

Lesson by Emma Bryce, animation by Kozmonot Animation Studio.