US President Barack Obama spoke for many when he said, "All in all, this has been a tough week."

During five days of terror, three people, including a Chinese graduate student, were killed watching the Boston Marathon, and more than 170 others were injured, some horrifically. A police officer at Massachusetts Institute of Technology and one of the bombing suspects were shot and killed. A million Bostonians were locked down in their homes as authorities searched for one of two brothers of Chechen heritage who had been in the United States for a decade and who had turned a well-loved, easygoing city into a war zone.

Out of a clear blue sky at a historic sporting event on Patriots' Day, innocent people were attacked while the world watched, aghast. There was an outpouring of grief for the victims: Lu Lingzi, 23, Martin Richard, 8, and Krystle Campbell, 29, killed in the blasts on April 15, Sean Collier, 26, the MIT police officer reportedly gunned down by the brothers on the night of April 18, and the countless maimed.