Pope Benedict XVI marked the end of 2011 with prayers of thanks and said humanity awaits the new year with apprehension but also with hope for a better future.
"Another year approaches its end, while we await a new one, with the trepidation, desires and expectations of always," Benedict said at the traditional New Year's Eve vespers service, as he delivered his homily from the central altar of St. Peter's Basilica on Saturday evening.
"With the spirit filled with gratitude, we prepare to cross the threshold of 2012, remembering that the Lord watches over us and takes care of us," Benedict said. "In him this evening we want to entrust the entire world. We put into his hands the tragedies of this world of ours and we also offer him the hopes for a better future."
Benedict, wearing gold-colored robes, arrived for the solemn ceremony standing aboard a raised, wheeled platform that ushers guided up the basilica's long center aisle.
The 84-year-old pontiff started using the device earlier in the year to reduce fatigue.
Benedict nimbly navigated the platform's two steps and knelt, apparently without difficulty, at the foot of the altar area as a choir of men and boys sang hymns.
Immediately after the 90-minute prayer service, the pontiff shed his liturgical vestments, donned a full-length white topcoat and rode aboard the popemobile into St. Peter's Square, to the surprise of many tourists.
He stepped down to walk briskly to a spot before the life-sized Nativity scene, where he knelt in silent prayer.
A towering Christmas tree, donated by Ukraine and twinkling with lights, sparkled in the center of the square.
Benedict then strode over to a contingent of the Swiss Guard band, which played "Silent Night" and other Christmas songs, and chatted in German with one of the guards in traditional colorful costume.
Benedict returned to the basilica Sunday morning to preside over New Year's Day Mass, an occasion the Vatican marks as world peace day.