Your time machine only has one charge so you can't go back and change it again. So what would be a reasonable change?
I go back and stop 9/11 from happening, I would love to see how different the world's view on privacy would be and I hope stopping 9/11 would stop both Iraq and Afghanistan and the CIA/NSA from gaining too much power.
9/11 is a common choice. But regardless of what you do to stop it, you would need to make sure people know what was going to happen so security measure post 9/11 will come into effect making travel safer and pray that Bush doesn't still want to kill all the middle eastern people regardless of background.
Make sure Bush was never elected. The 2000 election was a mess and Bush was...not the greatest to say the least.
In recent history, I would've prevented the assassination of JFK. I thin he was outstanding and getting the country to head in a very good direction...hence why he was assassinated.
Throughout all of history, I would have done what I could to save the Library of Alexandria. Can you imagine the amount of knowledge we lost?!?!
I always wonder about how linked the library of Alexandria is to the Vatican Library. Best way for people not to search for anything is to say its gone, lost in time.
Great mention nonetheless.
If it were only one possible event, for me it would have to be the signing of the Federal Reserve Act by Pres. Wilson. This effectively ruined America's sovereignty and put into place a new system of slavery.
I would try to prevent black friday, just to see what happens.