You mean that the Earth is spherical? You can look at the shadow of the Earth on the moon during the eclipse. It's (nearly) round.
If you could fly, you could get as high as suborbital heights to see the curvature of the Earth for yourself.
One example would be the stem cell reasearch, one side wants to cure diseases and save lives, the other is arguing whether a cell is a human being. Or the AIDS issues in Africa - you have one side teaching about safe sex and distributing condoms and the other side (well the Pope to be exact)...