Where does water boil at the temperature 37 °C (98.6 °F)?

The Armstrong limit or Armstrong's line is a measure of altitude above which atmospheric pressure is sufficiently low that water boils at the normal temperature of the human body. Humans absolutely cannot survive above this limit in an unpressurized environment. Above Earth, this begins at 18–19 km (11–12 mi; 59,000–62,000 ft) above sea level. The term is named after United States Air Force General Harry George Armstrong, who was the first to recognize this phenomenon