When you die, your body goes through a number of changes. First, your heart stops beating and your blood stops flowing. This means that your cells don’t get the oxygen and nutrients they need, and they start to die. Your muscles and organs begin to break down and decompose.
Your body also starts to swell as fluids build up. Your skin becomes pale and blotchy as your blood vessels lose their elasticity and leak fluids. Your eyes sink into their sockets and your hair and nails fall out.
As your body decomposes, bacteria and insects start to eat away at your tissues. This can cause a foul smell. The process of decomposition is hastened by warm temperatures and slowed by cold temperatures.
Once your body is fully decomposed, all that remains are your bones.