What is the human heart?

Put your hand on your chest... thump, thump, thump! Did you know that steady drumbeat is actually the hardest-working muscle in your entire body? Join Mira and Finn on an epic adventure inside the human body to discover exactly how your heart works! You won't believe the amazing science hiding just beneath your skin. Did you know your heart is only about the size of your fist, but it squeezes 100,000 times a day without ever taking a nap? We're going to shrink down and follow a single drop of blood as it zooms out of the heart, picks up fresh oxygen in your lungs, and races all the way down to your toes like a high-speed roller coaster! You'll find out how your body holds 60,000 miles of blood vessels—enough tiny tubes to wrap around the entire Earth more than twice! Discover why microscopic tunnels called capillaries force your red blood cells to line up single-file, and find out how a brilliant doctor unlocked the secret of the circulatory loop. Get ready for a mind-blowing journey inside you!