4000

There are a series of mountains in New England that are significant for their height. Each one rises at least four thousand feet above sea level. This may not seem that impressive compared to some of the peaks in places like Colorado, or the Himalayas, but compared to the rolling hills that surround them, these mountains are distinguished by Prominence, or the vertical separation between a peak and the low point of the highest ridge connecting it to a higher peak. In other words, these are very tall things that tower over everything else around it because of their height.
One of Jesus Christ's best tricks was to feed four thousand with only seven loaves of bread. It certainly begs the question, how big were the loaves, or how much did each person get? But it stands as a miracle, and rightly so.
A group in Boston called Silent March made a dramatic show of four thousand empty pairs of shoes, representing the annual gun death toll for youth age 19 and under in the U.S. Some shoes were sent to Silent March by family members of victims, while others were sent by concerned citizens: boots, slippers, sneakers, baby shoes, even a pair of pink ballet shoes.
Then there were "four thousand holes in Blackburn Lancashire", referred to in the Beatles song "A Day in the Life". It was a reference to the number of potholes in the roads, so many that they couldn't all be repaired. Over time, some had suggested other, more sinister meanings: a Typhoid outbreak that meant everyone had to be immunized - holes in arms, or unmarked graves of bodies of people that died during the German blitzkrieg on London during World War II. Whatever the source, potholes or corpses, now we know how many holes it takes to fill the Albert Hall.
Or at least that's what John Lennon had in mind when he wrote "A Day In The Life". It was a bit of hyperbole, comparing the number of holes to the number of seats in a very large theatre. There are actually more than six thousand five hundred seats in the Royal Albert Hall, which means that U.S. casualties in Iraq still have a ways to go before they could literally fill the Albert Hall. For now we'll just fill the orchestra and mezzanine.