the rare and supremely agreeable condition....

     Altogether it takes 7 billion billion billion (that's 7,000,000,000,000,000,000,000,000,000, or 7 octillion) atoms to make you.  No one can say why those 7 billion billion billion have such an urgent desire to be you.  They are mindless particles, after all, without a single thought or notion between them.  Yet somehow for the length of your existence, they will build and maintain all the countless systems and structures necessary to keep you humming, and to make you you, to give you form and shape and let you enjoy the rare and supremely agreeable condition known as life.
     That's a much bigger job than you realize.  Unpacked, you are positively enormous.  Your lungs, smoothed out, would cover a tennis court, and the airways within them would stretch nearly from coast to coast.  The length of all your blood vessels would take you two and a half times around the earth.  The most remarkable part of all is your DNA (or deoxyribonucleic acid).  You have a meter of it packed into every cell, and so many cells that if you formed all the DNA in your body into a single strand, it would stretch ten billion miles, to beyond Pluto.  Think of it: there is enough of you to leave the solar system.  You are int the most literal sense cosmic.

-Bill Bryson, The Body:  A Guide for Occupants