Learn Spanish (Latin America): Escalar esta montaña fue un reto más duro de lo que parecía. - Climbing this mountain was a harder challenge than it seemed.

When you compare an adjective to a whole clause (a phrase with its own conjugated verb), you use de lo que instead of just que. Here, we are comparing how hard it was (más duro) to how it seemed (parecía). If we were just comparing two nouns, like "a harder challenge than the other", we would use que.

Why is "Climbing" translated as Escalar (the infinitive) and not Escalando (the -ing form)?

In Spanish, when a verb acts as the subject or noun of a sentence, you must use the infinitive form (Escalar). The gerund form ending in -ando or -iendo is only used for actions that are currently in progress, like Estoy escalando (I am climbing).

Why does this sentence use the preterite fue but the imperfect parecía?

Fue (preterite) is used because the act of climbing the mountain is viewed as a single, completed event. However, parecía (imperfect) is used because how the mountain "seemed" was an ongoing impression or background state leading up to the climb.

Could I use estuvo instead of fue since the climb is over?