The 2011 World Youth Day celebrations in August were "a precious gift which gives hope for the future of the Church," Pope Benedict XVI said Wednesday during a general audience at Castel Gandolfo.

The pontiff described the six day festivities, which took place from August 15-21 in Madrid and were attended by nearly two million young pilgrims, as "a moving ecclesiastical event" and a "true waterfall of light."

"I thank God for this precious gift which gives hope for the future of the Church," he said.

The 84-year-old said the "irrepressible enthusiasm" of those who had come to celebrate the lavish Catholic youth festival in the streets of the Spanish capital had been proof of "a young faith, full of courage for the future."

Benedict XVI told the 2,000 pilgrims attending the general audience how pleased he was that the young faithful had not been "put off by the wind and rain" which had lashed the city during the event.

"The meeting in Madrid was a magnificent show of faith for Spain and the world, for all of us," he said. It was a chance for the young to "reflect, dialogue, tell each other about their experiences and pray together."

The leader of the world's 1.2 billion Roman Catholics announced the theme for the next World Youth Day, to take place in Rio de Janeiro in Brazil in 2013: "Go therefore, and make disciples of all nations." (Matthew 28:19).