The day the world went flat

I can't describe you to Everest,
nor the Marianas trench

Though...
it's true I've tread the lowest of valleys,
and climbed the highest of highs
I always managed to get back home,

And so...
once I got the word
of what was faced ahead
I slipped beyond the edge

I pay for all I've done in life
and for every word I've said