What are the highest impact projects (in any domain) that can be completed by humans?
Electromagnetic space launch system?
"Highest impact" in what form and for whom? A tribe in Amazonas might not even notice. Also, i.e. "nukes to everyone" might destroy our world, maybe better to ask for "best impact"?
Highest positive impact of most/all of the humans and other creatures on the planet. Mainly this can be reduced to: increased length and/or quality of life.
