All I can say is that I honestly thought it was a national shrine to shopping. I'm not joking.
The best way to describe the National Mall is lots of fields near the main museums and I honestly think that the best way to learn about the National Mall is to take a walking tour around it as you will learn so much more by going with a tour guide than relying on a book.
The memorable part for me was walking past the Vietnam Veterans Memorial and the World War II memorials. I don't know why but I seemed to soak up the history just by walking past there.
The Lincoln memorial at the West End of the National Mall was where we finished up with when we were on the walking tour and it was great. I can't remember the company's name though... Sorry but I'm sure if you just type walking tour Washington DC into Google you'll find something.
We just kind of walked around the National Mall one of the afternoons we were there and it was really relaxing just to kind of chill and relax after we had walked along way.