Some things seem huge or tiny to us, but we can never know their true size until we see them in comparison to something else. The blue whale has the largest heart compared to any living animal. Its heart is so big that a human could swim through its veins like tunnels. The tiniest animal heart belongs to fairyflies, and you'd need a microscope to see it. Using macro photography, we will see an object that looks like a deserted location from a fantasy novel, but in fact, it's just human cheeks.

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