Learn Italian: Ci sono volute due ore in autostrada. - It took two hours on the highway.

With the impersonal verb volerci, the time itself is actually the subject of the sentence. Here, the subject is due ore (two hours), which is plural. Italian literally says "Two hours were needed." Because the subject is plural, the verb must be plural (sono volute).

Why does the past participle end in "-e" (volute)?

In the past tense (passato prossimo), verbs that use essere as a helping verb must match their ending to the subject. Because the subject due ore (two hours) is feminine plural, the past participle voluto changes its ending to match, becoming volute.

Why does this sentence use essere (sono) instead of avere?

The verb volerci always uses essere in the past tense. Remember that volerci is impersonal (general). If you wanted to make it personal and say "I took two hours," you would use the verb metterci, which uses avere in the past tense: Ci ho messo due ore.

What is the ci doing at the beginning of the sentence?