I can confidently say that CRISPR - or perhaps more generally, genetic engineering - is going to change the course of human history, if it hasn't already.
CRISPRs (clustered regularly interspaced short palindromic repeats) were first discovered in 1987 in a bacteria called Escherichia coli, though what CRISPRs actually did remained unknown. In 1995, Francisco Mojica (who had been studying CRISPRs since 1989) published a paper detailing the existence of CRISPRs in a wide array of microbes. Which invited the question, "Why do microbes from across the world all have this same genetic tool?"
A little over ten years later, it was determined that CRISPRs were part of an ancient defense system employed by bacteria against viruses. CRISPRs, along with the enzyme Cas9, were used by bacteria to precisely edit their DNA to include snippets of virus's genetic material, thereby creating a genetic memory to ward off future invaders.
Not long after, it became apparent that one of the biggest scientific discoveries was unfolding, and that it would likely change the future of humanity. CRISPR allowed us to precisely edit human DNA, turning on or off specific genes or even adding genetic sequences. Oh and it's about 1000 times cheaper than existing gene editing methods, which is huge.
Since the mid-2000s, CRISPR researchers have been progressively refining the technique. With each advance, DNA becomes more similar to software. The long-term picture thus comes into focus: human genetic engineering. And other possibilities are just as mind-blowing.
Imagine only having to take a breath once every 45 minutes. Or being able to run at a full sprint for miles without becoming winded. These are some of the possibilities for "smart blood" or genetically enhanced blood. The concept is elaborated on in the article Human Enhancement: The Scientific and Ethical Dimensions of Striving for Perfection by David Macsi:
It’s also possible that enhanced blood will be genetically engineered rather than synthetically made. “One of the biggest advantages of this approach is that you would not have to worry about your body rejecting your new blood, because it will still come from you,” says Oxford University’s Sandberg.
Regardless of how it is made, one obvious role for enhanced or “smart” blood would be to increase the amount of oxygen our hemoglobin can carry. “In principle, the way our blood stores oxygen is very limited,” Sandberg says. “So we could dramatically enhance our physical selves if we could increase the carrying capacity of hemoglobin.”
According to Sandberg and others, substantially more oxygen in the blood could have many uses beyond the obvious benefits for athletes. For example, he says, “it might prevent you from having a heart attack, since the heart doesn’t need to work as hard, or it might be that you wouldn’t have to breathe for 45 minutes.” In general, Sandberg says, this super blood “might give you a lot more energy, which would be a kind of cognitive enhancement.”
If you haven't already, watch this video from Kurzgesagt – In a Nutshell, it's a fantastic primer on CRISPR and genetic engineering's potential impact on humanity: