I built a wall

this is a big work.
very big even huger than any building you can see or hear.
and I have spent more than 10 years to do on it.
How big is it ?maybe you want to ask ?
I can't tell the exactly accurate numbers.
It highs one thousand meters thick one thousand meters.
But it can only hold one person just me.
In this big wall ,I Can't see any lights Because I haven't build it between tropics.