The distances remain the same, but the perceived distance has shrunk to such an extent than an attack felt in one part of the world is bound to affect another. Terrorism differs from war in a number of ways. For one, everything is a target. Whereas targeting civilian targets is prohibited by the Geneva Convention for parties in war, terrorists recognize no such rule. Civilian targets cause the most horror and receive the most attention. The following graph shows American military casualties in various wars and global casualties to terrorist attacks.

The significance of the terrorism entry is that it only covers eight years, and, from those years alone, is more than a third of the way from the American casualties in WWII. The actual number is sure to be much higher, as records of terrorist attacks go as far back as the 1960s.

The global map did not take into account repeated attacks in a country. Multiple markers would have made navigating very difficult. Instead, the chart below does take multiple attacks within a country into account. There may be some surprising entries at first glance, but the countries must be thought of in the context of their history. Spain, for example, has a high number of attacks, most if not all attributable to the Basque movement–a terrorist organization in Spain’s eyes.

51 countries are listed on the above chart. Tree #140 stands for 51 countries and at least 161,834 deaths. So now we return to the Arlington National Cemetery and the question of space. The Millennium Project currently underway adds 27 acres to the grounds, allowing for an additional 30,000 internment sites. To do so, some trees in its proposed area of expansion will need to be removed, some of which are more than 250 years old. There are over 400,000 people buried in the cemetery. If the all of the trees currently in the cemetery were utilized as memorials, as Tree #140 is, each tree would commemorate the lives of roughly 47 people. Considering that’s 161,787 less than the burden placed on Tree#140, the idea doesn’t sound unreasonable.