I'd guess my bones were about 6 years old

In our lifetime we will have a "new" set of bones every 10 years. Our femurs are never more than six months old. The engineer of the Eiffel Tower modeled the structure after researching the layout of our bones. They're strong. And so is the Eiffel Tower.

I find myself remembering everything I am learning lately.

I've never studied the human body and been so completely aware of the happenings of my own body. I sat at my desk the other day bending and moving my fingers, watching my own digits as if they were not my own. My skin and bones and blood and nerves, all there in perfectly organized systems. I thought about fine motor skills and the fibers in every muscle that were enabling such movement. I thought about actin, and myosin, and sarcomeres, and troponin. I thought about how hard all my cells must be working, squinting to focus on my fingers as I held them in front of my eyes, as if I could see my them respire and send the CO2 to my lungs for me to exhale. Such a triumph of evolution.

Life is so insanely complicated. Our bodies are temples after all. I wonder where else, I mean exactly where else the carbon in my body has been.