In minutes, patient children bolted past the snipped shards of ribbon for the swingsets, jungle gym, slides and a 66-foot zip-line at the playground named Kayla's Hands for a young American taken too soon. Her parents beamed listening to the joyful noise.
"I didn't know Kayla but I sense in every account of her ordeal, the true meaning of humility," McCain said in a short speech.
She adored the Syrian refugee children she worked with in southern Turkey, her friends have said.
This year her father Carl worked with the Prescott Kiwanis Club, of which he is a former president, to raise money from donors such as the Arizona Diamondbacks for the new playground, which will also finally offer handicapped kids in the high desert town a place to safely frolic. It has been an emotional anchor for him to cling to, happily adjusting the plans in recent months for the bouncy floor matting and the zip-line, which Kayla's mom loves to sail down.
"We can feel Kayla here," Carl Mueller said. "When the wind blows just right, we can hear her makin' her music."
The still grieving dad said he and Marsha will "be spending a lot of time here."
"She lived her life for others, she used her hands to relieve suffering. She was not just sympathetic to the plight of the less fortunate, she was moved to action," McCain told the crowd. "Her fellow captives spoke of her as an inspiration. Brave and defiant when she was abused and threatened, consoling and selfless to those who shared her suffering."
Former ISIS hostages have spoken of her selflessness in captivity, where she tried to cheer them up, gave them strength and once even sacrificed an opportunity to escape to ensure fellow captives got away, ABC's "20/20" reported last night in the segment, "The Girl Left Behind," after more than two years of investigation.
In one incident in March 2014, Mueller even stood up to British ISIS executioner Jihadi John to correct him when he told other hostages that she had converted to Islam.
"Her love now echoes in the joy and laughter of children. What a fitting -- what a fitting tribute," McCain said, his voice finally breaking with emotion, as Marsha Mueller reached over to hug the war hero senator.
The Rev. Kathleen Day of Northern Arizona University, who Kayla befriended in college and who later became a close confidante of Carl and Marsha Mueller during her hostage ordeal, recalled how the young do-gooder from Arizona had said that "it's never goodbye among friends" whenever she left Prescott for Turkey and Syria or other far-flung destinations.
"Today Prescott says to Kayla Jean, we will always love you, and indeed it's never 'goodbye' because her spirit will live on in the laughter and the joy and the compassion and the friendship of this playground," Day said.