There’s no way of knowing exactly how many of Henrietta’s cells are alive today. One scientist estimates that if you could pile all HeLa cells ever grown onto a scale, they’d weigh more than 50 million metric tons—an inconceivable number, given that an individual cell weighs almost nothing. Another scientist calculated that if you could lay all HeLa cells ever grown end-to-end, they’d wrap around the Earth at least three times, spanning more than 350 million feet. In her prime, Henrietta herself stood only a bit over five feet tall.
