One year ago today, the detonation of two improvised bombs near the finish line of the Boston Marathon killed three people, injured more than 260 others, and shattered a day traditionally filled with joy and camaraderie. Although the bombing immediately extinguished the celebration, it sparked an outpouring of extraordinary work and compassion that continues to this day. Residents of Boston, the Commonwealth of Massachusetts, and beyond rallied to help those injured by the bombs. It is a testament to the extraordinary care and preparation by first responders and staff members at all Boston-area hospitals that only three people died. Many of the wounded were taken to teaching hospitals affiliated with Harvard Medical School. The medical school and its institutions take time today to mourn this senseless tragedy, pray for those who lost a loved one or who themselves still bear physical and emotional scars from the bombing, and acknowledge the work of first responders, emergency department staff, and others who have been part of the healing effort.