Astonishing
Part of speech: verb
Definition: To surprise greatly.
Example sentence: Isn't it astonishing that all these secrets have been preserved for so many years just so we could discover them!
Staggering
Part of speech: adjective
Definition: Incredible, overwhelming, amazing.
Part of speech: verb
Definition: Sway unsteadily, reel, or totter.
Example sentence: We are not made safe from terrorists by helicopters, or missiles or boots on the ground. Nor is it drones, torture or digital dragnets that protect us. What makes us as individuals safe from a terror attack is the staggering probability that we will be elsewhere when one occurs.