What scientific discovery or biological concept has most deepened your sense of wonder about the natural world?

What happens if you make everybody believe that you're going to talk to them forever but actually after spending a lot of time with them getting bored you suddenly disappear and never return?
Is Trump's understanding of American history -- as reflected in the changes he is forcing on the Smithsonian -- really just more right-wing whining about "woke" and a blatant attempt to paint America as a white Christian nationalist state?