Above is a great video of human Mars exploration evangelist Dr. Bob Zubrin.
I met the good man twice. First in 1998 as a speaker at the International Space University (ISU) Summer Session Programme (SSP) at Cleveland State University. He was so fired up on Mars and put so much energy into his presentation that I was seriously worried about his health. I did buy his book 'the Case for Mars' after his lecture and enjoyed it every word. It was the best presentation of that hot summer. The second meet-up was at Houston airport where I accidentally ran in to him in the Delta airlines lobby after the World Space Congress in 2002. He was more relaxed then and we chatted a bit about in how many ways things were going of course in the US space programme.
It is good to see him still alive and kicking in this video from from 2015. I watched it a few times and you should really check out what happens at 1:59, when he shifts to his second reason why humans should go to Mars. He huffs and puffs a bit, and off he goes again. I did not need to be worried about his health back in 1998, it is how he organizes and charges his mind! He is a force of nature.
I could not agree more with what the man says about the three main reasons why humans should go to Mars. It is where the science is. It is where the challenge is. It is where the future is. The only nuance that would make his storyline even stronger is the third reason. He says '[For the future,] this [Human Mars exploration] is the most important thing that we could do in this time'.
If putting priority on things, then I believe that keeping our Earth habitable for future generations is higher on the list. We, the Earthlings, should, before this decade is out get rid of fossil fuels, poverty and borders and embrace nuclear energy. But let me be clear, I do believe, this does not at all stand in the way of endeavouring towards Mars at the same time. I actually think, that the human Mars exploration challenge will actually accelerate how fast we will get rid of fossil fuels, poverty and borders on Earth. So let's go, full steam ahead to the red planet!