Watch a lung incredibly expand with air like a balloon

What you're looking at is a cat lung being blown up with a straw. I know. It's ginormous. More ginormous than what you would think is inside a cat. But that's because lungs are incredibly expandable. What looks like a pile of bloody meat inflates into this perfectly pink balloon.

Morphology explains:

Here, a set of cat lungs is inflated with a straw. Comprised of hundreds of millions of microscopic air sacks called aveoli, Mammalian lungs harbor air capacity that is difficult to believe unless seen. The color of the entire organ lightens into a soft pink, as each microscopic sac fills with air.

Beautiful.