Annabeth sky

Then the darkness above Luke began to crumble, like a cavern roof in an earthquake. Huge chunks of black rock began falling. Annabeth rushed in just as a crack appeared, and the whole ceiling dropped. She held it somehow—tons of rock. She kept it from collapsing on her and Luke just with her own strength. It was impossible. She shouldn’t have been able to do that.Luke rolled free, gasping. “Thanks,” he managed.
“Help me hold it,” Annabeth groaned.
Luke caught his breath. His face was covered in grime and sweat. He rose unsteadily.
“I knew I could count on you.”

"From holding the sky," Thalia muttered, as if she'd read my mind. "The weight should've killed her."
"I don't understand," I said. "Why can't Artemis just let go of the sky?"
Atlas laughed. "How little you understand, young one. This is the point where the sky and the earth first met, where Ouranos and Gaia first brought forth their mighty children, the Titans. The sky still yearns to embrace the earth. Someone must hold it at bay, or else it would crush down upon this place, instantly flattening the mountain and everything within a hundred leagues. Once you have taken the burden, there is no escape." Atlas smiled. "Unless someone else takes it from you."

"Annabeth took it!"
"She barely survived. She had the spirit of a true huntress. You will not last so long."
"I'll die anyway," I said. "Give me the weight of the sky!"
I didn't wait for her answer. I took out Riptide and slashed through her chains. Then I stepped next to her and braced myself on one knee—holding up my hands—and touched the cold, heavy clouds. For a moment, Artemis and I bore the weight together. It was the heaviest thing I'd ever felt, as if I were being crushed under a thousand trucks. I wanted to black out from the pain, but I breathed deeply. I can do this.
Then Artemis slipped out from under the burden, and I held it alone.
Afterward, I tried many times to explain what it felt like. I couldn't.
Every muscle in my body turned to fire. My bones felt like they were melting. I wanted to scream, but I didn't have the strength to open my mouth. I began to sink, lower and lower to the ground, the sky's weight crushing me.
Fight back! Grover's voice said inside my head. Don't give up.
I concentrated on breathing. If I could just keep the sky aloft a few more seconds. I thought about Bianca, who had given her life so we could get here. If she could do that, I could hold the sky.