Axiom systems feel like the ordinal numbers: you can keep building upwards as far as the eye can see, and even farther and you run out of useful reasons to do it long before you run out of axiom systems or numbers.

"One!" "Two!" "Three!" "Infinity!" "Infinity plus one!" "Infinity plus two!" "Infinity plus infinity!" "Infinity times infinity!" "Infinity to the power of infinity!" "Infinity to the power of infinity to the power of infinity!" "The supremum of all ordinals that can be expressed in a finite sequence of symbols!" "The supremum of all ordinals that can be expressed in a finite sequence of symbols plus one!"