The boot memorial began at Fort Hood, Texas, in 2014 and is displayed annually at July 4. Each of the 7,000 boots represents a servicemember who has died since 9/11 and features their photo, information and an American flag. (Rose L. Thayer/Stars and Stripes)

Visitors have written messages across many of the boots on display. "Paratroopers are always with us. Sometimes they slip away. Be not sad!" was written across the boot representing Army Sgt. Clinton K. Ruiz, who died Oct. 25, 2012, while deployed in support of Operation Enduring Freedom in Afghanistan. (Rose L. Thayer/Stars and Stipes)

Visitors to the boot memorial, which is presented annually at Fort Hood, Texas, often tie together the boots of battle buddies or troops who died in the same action. The boots representing the 13 people killed during a mass shooting at Fort Hood on Nov. 5, 2009 are tied together and have been adorned with Tootsie Roll Pops. (Rose L. Thayer/Stars and Stripes)

Grasiela Rangel and her children Ava, 3, and Eddie, 5, look through the boot memorial at Fort Hood, Texas, on July 3. Each of the more than 7,000 boots on display represent the life of a servicemember lost since 9/11 and include a photo of the servicemember. Rangel, a military spouse, volunteered to update the photos, which over time can become faded by the sun. (Rose L. Thayer/Stars and Stripes)

More than 7,000 boots are on display at Sadowski Field at Fort Hood, Texas, to represent the servicemembers of each branch of the military who have died since 9/11. The boots will remain on the field through July 7. ( Rose L. Thayer/Stars and Stripe)

The boots representing Army Sgt. James Johnston and Army Master Sgt. Michael Riley, who died June 25 in Afghanistan, were most recently added to a display of more than 7,000 boots representing servicemembers who have died since 9/11. The display is at Fort Hood, Texas, through July 7. (Rose L. Thayer/Stars and Stripes)