The wall was originally made by the different provinces of China to keep the others out but in 221BC, Qin Shi Huang conquered all of the other states and made a united China. He unified the wall to keep other nations out rather than having the in-fighting that had plagued China for centuries. The current wall was most likely remade by the Ming dynasty in the 14th century.
You have to drive about an hour outside of Beijing to get to the closest portion of the wall that is accessible and walkable. The steps are uneven and worn. There are watch towers every so often and as soon as you climb past the first one the crowds thin out. It seems like people go and climb a little and say they have done it.
This is the relatively flat (compared to the rest) area that you can enter the wall. If you look up, yes that's what you climb. This is a country of hills and mountains. And that isn't fog...it is mostly smog.
A variety of warnings while climbing. The no climbing refers to the actual watch tower, not the wall. LOL
This is taken looking down from the first watch tower you get to.
While this is looking up from the same watch tower. As you can see it just keeps going up and up.
A good view of the stairs. A lot of them are super worn by the handrail because more people walk there.
At the base of this section where most people park they have a few traditional buildings.
I found the climb at the Great Wall to not be too bad, especially after the week before's climb up Laoshan Mountain. I went on a Sunday and while the first section was crowded, I didn't think it was unreasonable. I'm glad I went and did this.