What would you put in a box to give people in the future an idea of life today.Why?

I would put a cell phone in a box. People use cell phones and tablets a lot today. We use them to communicate, to learn and share information. We use our phones as a notebook, a map, a camera and so on. We store photos, watch videos, play games, listen to music, and the list can be endless. A cell phone has become our indispensable assistant, and now we can barely imagine our life without it.