A closer look

Western medicine loves to pat itself on the back for discovering how blood circulates in the 17th century, completely ignoring that a Syrian polymath beat them to the punch by 400 years. In the 13th century, Ibn al-Nafis accurately described pulmonary circulation—how blood moves from the heart to the lungs and back—while European doctors were still convinced your veins were filled with "humors" and that strapping leeches to your forehead was peak healthcare.