Explanation:
* Independent Clauses: "We decided to go for a hike" and "we were rewarded with breathtaking views from the mountaintop" are both complete sentences with a subject (we) and a verb (decided, were rewarded).
* Dependent Clause: "Although the rain poured relentlessly" is a dependent clause because it cannot stand alone as a complete sentence. It starts with a subordinating conjunction ("although") and provides additional information about the main clause.
* Compound-Complex: The sentence combines two independent clauses ("We decided to go for a hike" and "we were rewarded with breathtaking views from the mountaintop") with a dependent clause ("Although the rain poured relentlessly").
Therefore, the sentence meets the criteria of a compound-complex sentence.