The hike was long and tough, but the view from the summit was worth it.

was 是动词 be 的过去式，表示"是"的状态。 worth 是形容词，意思是"值得的"，表示某事物具有足够价值或重要性。 it 在这里指代前面提到的"漫长而艰难的徒步"。 was worth it 这个短语表示"（付出努力后）得到的结果是值得的"，强调经历困难后获得的回报让人满意。