Structure of Haemoglobin: Haemoglobin is an aggregation of four globular proteins (typically two alpha and two beta subunits), each with an embedded haeme group. Each haeme group allows the binding of an oxygen molecule.
Here's another intriguing case from the Guinness World Records. In 1964, a 17-year-old high school student named Randy Gardner beat the world record for sleep deprivation by staying awake for 264 hours (11 days) without using any stimulants.
There were several attempts in a world history to achieve a record of being awake longer than anybody else. Randy Gardner, a 17-year-old student from San Diego, California, the USA, managed to stay awake for 264.6 hours (that is 11 days and 24 minutes) in 1964. His record entered The Guinness Book of Records.