needed leverage.
Finding the glass wall again, he placed one hand on it to guide him as he raced in the dark toward the far end of the vault. The back wall loomed suddenly, and he collided with it, crushing his shoulder. Cursing, Langdon circled the shelf and grabbed the stack at about eye level. Then, propping one leg on the glass behind him and another on the lower shelves, he started to climb. Books fell around him, fluttering into the darkness. He didn't care. Instinct for survival had long since overridden archival decorum. He sensed his equilibrium was hampered by the total darkness and closed his eyes, coaxing his brain to ignore visual input. He moved faster now. The air felt leaner the higher he went. He scrambled toward the upper shelves, stepping on books, trying to gain purchase, heaving himself upward. Then, like a rock climber conquering a rock face, Langdon grasped the top shelf. Stretching his legs out behind him, he walked his feet up the glass wall until he was almost horizontal.
Now or never, Robert, a voice urged. Just like the leg press in the Harvard gym.
With dizzying exertion, he planted his feet against the wall behind him, braced his arms and chest against the stack, and pushed. Nothing happened.
Fighting for air, he repositioned and tried again, extending his legs. Ever so slightly, the stack moved. He pushed again, and the stack rocked forward an inch or so and then back. Langdon took advantage of the motion, inhaling what felt like an oxygenless breath and heaving again. The shelf rocked farther.
Like a swing set, he told himself. Keep the rhythm. A little more.
Langdon rocked the shelf, extending his legs farther with each push. His quadriceps burned now, and he blocked the pain. The pendulum was in motion. Three more pushes, he urged himself.
It only took two.
There was an instant of weightless uncertainty. Then, with a thundering of books sliding off the shelves, Langdon and the shelf were falling forward.
Halfway to the ground, the shelf hit the stack next to it. Langdon hung on, throwing his weight forward, urging the second shelf to topple. There was a moment of motionless panic, and then, creaking under the weight, the second stack began to tip. Langdon was falling again.
Like enormous dominoes, the stacks began to topple, one after another. Metal on metal, books tumbling everywhere. Langdon held on as his inclined stack bounced downward like a ratchet on a jack. He wondered how many stacks there were in all. How much would they weigh? The glass at the far end was thick...
Langdon's stack had fallen almost to the horizontal when he heard what he was waiting for - a different kind of collision. Far off. At the end of the vault. The sharp smack of metal on glass. The vault around him shook, and Langdon knew the final stack, weighted down by the others, had hit the glass hard. The sound that followed was the most unwelcome sound Langdon had ever heard.
Silence.
There was no crashing of glass, only the resounding thud as the wall accepted the weight of the stacks now propped against it. He lay wide-eyed on the pile of books. Somewhere in the distance there was a creaking. Langdon would have held his breath to listen, but he had none left to hold.
One second. Two...
Then, as he teetered on the brink of unconsciousness, Langdon heard a distant yielding... a ripple spidering outward through the glass. Suddenly, like a cannon, the glass exploded. The stack beneath Langdon collapsed to the floor.
Like welcome rain on a desert, shards of glass tinkled downward in the dark. With a great sucking hiss, the air gushed in.
Thirty seconds later, in the Vatican Grottoes, Vittoria was standing before a corpse when the electronic squawk of a walkie-talkie broke the silence. The voice blaring out sounded short of breath. "This is Robert Langdon! Can anyone hear me?"
Vittoria looked up. Robert! She could not believe how much she suddenly wished he were there.
The guards exchanged puzzled looks. One took a radio off his belt. "Mr. Langdon? You are on channel three. The commander is waiting to hear from you on channel one."
"I know he's on channel one, damn it! I don't want to speak to him. I want the camerlegno. Now! Somebody find him for me."
In the obscurity of the Secret Archives, Langdon stood amidst shattered glass and tried to catch his breath. He felt a warm liquid on his left hand and knew he was