Spanish Dictionary

I need to write you one more sentence. This is what my teacher told me and the German language is so difficult. So please, as a last favor, would you please write the sentence for me in German?
The climb was much exhausting than I had presumed. I had forgotten that we were at high altitude where there is less oxygen and that every step required double effort. It was a great exercise.
We stayed there for a few hours observing the hugh ice blocks breaking off and falling into the icy waters leaving a water splash of over 100 meters. Each splash was followed by a dull thunder.
The climb was much exhausting than I had presumed. I had forgotten that we were at high altitude where there is less oxygen and that every step required double effort. It was a great exercise.
We stayed there for a few hours observing the hugh ice blocks breaking off and falling into the icy waters leaving a water splash of over 100 meters. Each splash was followed by a dull thunder.