The air rushing through my lungs.
The wind on my face.
The scenery as it passes by.
The hard-earned sweat on my brow (and various other unmentionable places).
The knowing glance shared between runners as we pass.
The feel of my feet pushing off the pavement.
The feel of my muscles working together as hard as they can.
Knowing my body has given all it can...
...and knowing my willpower can push it to give even more.
And finally, the feeling of crossing that finish line, hearing the cheers and having the medal placed around my neck and knowing I gave it my all.
This is why I run.