Kal could've done it all on his own -- located them, gathered them up, destroyed them -- but symbolically it would've never meant as much.
The President realized this. That was why she saw to it that it be done another way: through legislation, through law enforcement, through voluntary surrender.
She went on TV, President Lee did, and she held up an object before the nation, before the world, and she said:
"This is the last gun on Earth. The last gun that will ever be on Earth. Once it is destroyed... there will never be another."
President Lee raised the gun and pointed it in the air. "This shot I fire... will be the last ever fired upon this planet. Listen closely, citizens of humanity, for this is a sound you will never hear again!"
She pulled the trigger. The gun went off. The last bullet ever fired shot up into the clouds... where Kal caught it in his palm.
The planet cheered.
Kal flew back down to Earth and landed next to President Lee at the podium. He handed her the bullet. She handed him the gun. Kal held it high for all the world to see. Then he said:
"With your permission, Madame President...."
Sophia Lincoln Lee nodded.
"God bless the human race," she said.
Then Kal reared back... and threw the last gun into the sun.
The planet wiped a tear from its eye.
President Lee took the podium once again.
"What we have done here today is an accomplishment to be shared by all mankind. We have rid the world of its deadliest weapon. No, the killing will not stop. But this form, at least, will be forever ended. This next step, I realize, is not one with which everyone has agreed. But it must be done. Once banished, we must ensure that such destructive knowledge never again finds its way into the human heart."
Anna Taz, Sorceress Supreme, inside her tower heard the keywords delivered. Now was her time to act. From inside a building that possessed no windows nor doors, Anna Taz cast the greatest spell of her life. The collective willpower of all humanity served as her fuel. The desire was this: to forget. Not merely the existence of guns, but also all of the pain and suffering that they had ever brought. Her task: to erase this dark knowledge forever from the human race.
No one would ever conceive of a gun again.
No one would ever remember that they had existed.
And so Planet Earth forgot. Even President Lee, the engineer of this triumph. Even Kal, the world's foremost protector. Even Anna Taz herself, as the worldwide spell weakened and dissipated. The erasure must be complete.
Laws had banned them. The military had surrendered them. Kal had collected them.
Now guns were no more.
And perhaps somewhere in heaven, God smiled, knowing that his children had just grown up, a little.