1,7 (moments in time)

But sometimes, the events reach epic proportions.  These ones are the moments in time.  It's the age-old "where were you when that happened" question.  Everyone has a story, because it's these stories that define who we are as a people.  They set forth the meaning of our existence.  The "where were you" defines "who we are."

Because they are moments in time, they are the events that inextricably link us together as a nation.  These events bring us together.... they tear us apart.  They bring us joy and they bring us sorrow.  They inspire our dreams... and our nightmares.  They are our moments in time.

Some rank it as one of the 7 wonders of the world.  An incredible feat of engineering is constructed.

While another is razed.

How about this list of presidential assassinations?  At least these are the ones on wikipedia. 

You've got the unsuccessful...

(scrolling list, text only)

Andrew Jackson
Abraham Lincoln
Theodore Roosevelt
Herbert Hoover
Franklin D. Roosevelt
Harry S. Truman
John F. Kennedy
Richard Nixon
Gerald Ford
Jimmy Carter
Ronald Reagan
George H.W. Bush
Bill Clinton
George Bush
Barack Obama

the successful...

(scrolling list, text only)

Abraham Lincoln
James Garfield
William McKinley
John F. Kennedy

and there's even a couple maybes.  I didn't know about this.  I should probably brush up on my U.S. history.

(scrolling list, text only)

Zachary Taylor
William Harding

And for every triumph

First Moon Landing 1969
http://www.youtube.com/watch?v=RMINSD7MmT4
:04 - :14 ("That's one small step for man, one giant leap for mankind")

There's always a tragedy

Challenger Disaster live on CNN
http://www.youtube.com/watch?v=j4JOjcDFtBE

1:31 - 1:46 (explosion)
2:01 - 2:10 (possible explosion)
2:16 - 2:23 (confirmation)