9/11
when was 9/11
what is September 11 2001
who discovered gravity
what is Isaac Newton
when was gravity discovered
what is 1686
which tower fell first
what is the south
when did we launch our first satellite
what is October 4 1957
which plane did people fight back
what is flight 93
when was the first spaceship launched
what is April 12 1981
how many casualties on 9/11
what is 2,996
when was the Hubble space telescope launched
what is April 24 1990