Death is an inevitable part of life. From time to time, we all consider what will be the manner of our death. Although morbid, “how will I die?” is a question we harp on at some point in our life. Surprisingly, there is only, technically, one way for us to die: lack of blood flow to the brain, which means no oxygen and no glucose. Now what will ultimately cause that fateful lack of blood flow is the real mystery.

If you live in a developed country, like the United States, severe heart complications could cause the stoppage of blood flow to the brain. Heart disease, stroke, and respiratory illnesses are the leading cause of death in richer countries, like the U.S. While people in under-developed countries also die of heart disease and stroke, their lack of blood flow to the brain will most likely be caused by respiratory illness, HIV/AIDS, and diarrhea.

Respiratory illnesses are usually the result of breathing in smoke, but in developed countries that smoke tends to come from cigarettes, and in under-developed countries it comes from cooking with smoky fuels, like wood or animal feces. Even though HIV/AIDS is also a big killer in the U.S., people in the poorer countries are at a higher risk due to a lack of condoms, proper medication, and safe sex education. No matter what eventually causes the deadly lack of blood flow to the brain, the result is the same: We all die.