pope_benedict.jpgMADRID (AP) _ Pope Benedict XVI warned Thursday at the start of a visit to crisis-hit Spain that Europe won't be able to emerge from its economic woes unless it realizes that economic policy cannot be guided by a profit-driven mentality alone. He said the continent must take into account ethical considerations that look out for the common good.

Benedict made the comments as he traveled to Spain's capital for the Catholic Church's World Youth Day, the Catholic festival held once very three years that is expected to draw 1 million young people from 193 countries for a week of bonding, praying and partying in Madrid's streets _ normally deserted in August.

Hundreds of thousands of them lined Madrid's main boulevards to welcome the pontiff as he arrived for a four-day visit, a day after a protest against his trip turned violent. The screaming, sun-baked fans threw confetti on his car as he entered Madrid's Plaza de Cibeles for his official welcome ceremony Thursday night.

Benedict urged the crowd flying flags from around the world to root their lives in Christ and resist the temptation to follow secular trends, such as euthanasia and abortion, saying they lead to nothing since they don't lead to God.

“Indeed, there are many who, creating their own gods, believe they need no roots or foundations other than themselves,'' he warned. “They take it upon themselves to decide what is true or not, what is good and evil, what is just and unjust; who should live and who can be sacrificed in the interests of other preferences.''

He drew laughter and cheers when he briefly donned a straw sombrero presented to him by a young man, then a flower lei by a woman.

As he arrived, Benedict reached out to all young people, saying he understood the desperation many felt because of today's economic uncertainties.

“The economy doesn't function with market self-regulation, but needs an ethical rationale to work for mankind,'' he told reporters traveling aboard the papal plane. “Man must be at the center of the economy, and the economy cannot be measured only by maximization of profit but rather according to the common good.''

Benedict explored the theme more fully in his 2009 encyclical “Charity in Truth,'' in which he called for a new world financial order guided by ethics, dignity and the search for the common good. While he hasn't given many specific prescriptions since, his banker _ Ettore Gotti Tedeschi, head of the Vatican bank _ has been penning proposals to fix Europe's debt mess in the Vatican newspaper on a regular basis.

On Thursday, Benedict's call was welcomed by Spaniards, who have seen their economy sputter while the government battles its debt woes. Young Spaniards in particular are growing increasingly frustrated at their grim work prospects amid Spain's nearly 21 percent unemployment rate, a eurozone high.

“It's good to see the pope addressing these issues and giving us Spaniards some direction as to where to go to get out of this crisis, which worries so many young Spaniards,'' 27-year-old schoolteacher Fernando Sanchez said.

“It's not a realistic message, it's an idealistic one,'' he said. “But sometimes ideals can become reality. He sets high goals and then we have to see how to achieve them.''

This is Benedict's third trip to Spain as pope, cementing its reputation as ground zero in his campaign to reinvigorate the faith in places where Catholicism has fallen by the wayside. Laws passed under Socialist Prime Minister Jose Luis Zapatero allowing gay marriage, fast-track divorce and easier abortions have deeply angered the Vatican, which sees the once staunchly Roman Catholic country as a battleground for the future of the faithful in Europe.

Many Spaniards have balked at the cost of Benedict's visit at a time of economic difficulty. Many have cited the fact that pilgrims are getting deeply discounted subway and bus tickets while such prices for everyone else went up 50 percent this month.

Vatican Radio responded to the critics Thursday, noting that the (euro) 50 million ($72 million) tab for staging World Youth Day is being paid for by the participants themselves, some private donors and the church. Critics say the organizers' estimate doesn't include security costs and is a fraction of the total.

On Wednesday night, about 5,000 people opposed to the pope's visit marched peacefully to Madrid's central Puerta del Sol plaza, which has been the epicenter of Spain's antiestablishment protests since May. A smaller number of protesters then clashed with riot police; police said eight demonstrators were arrested and 11 people were injured.

“People were going really crazy but, at the same time, God wants all of us to be here and I know that he'll like protect us all while we're here,'' said Holly Springfield, a 17-year-old American who witnessed the protest and said she was a bit shaken by it.

Another protest targeted the organizers directly: the World Youth Day website was up and down all day thanks to what it said were “hacking attacks.''

But Benedict arrived in Madrid on Thursday to a boisterous welcome from young people with their faces painted the colors of the Spanish flag chanting: “These are the pope's young people!'' A cordon of youngsters decked out in faux Swiss Guard uniforms greeted Benedict on the tarmac at Madrid's Barajas airport, along with Spain's King Juan Carlos and Queen Sofia.

Zapatero and conservative opposition leader Mariano Rajoy, the man forecast to take power in November elections, also were present.

Clouds and a breeze kept Madrid's notoriously hot August temperatures at bay, though the mercury inched up later in the day as the sun broke through.

In a speech delivered on the tarmac in Spanish, Benedict referred to the precariousness many young people see in their future.

“Many young people look worriedly to the future, as they search for work, either because they have lost their job or because the one they have is precarious or uncertain,'' Benedict said. He urged young people to keep fast in their faith.

“With God beside them, they will possess light to walk by and reasons to hope, unrestrained before their highest ideals, which will motivate their generous commitment to build a society where human dignity and true brotherhood are respected,'' he said.

The king also referred to the sense of hopelessness many young people feel, saying today's youth are “frustrated by the lack of personal and work possibilities, and rebel against the serious problems facing the world today.''

On Tuesday, police arrested a chemistry student working as a volunteer for the pope's visit on suspicion he was planning a gas attack on protesters opposed to the pontiff's visit, officials said. The 24-year-old Mexican student, Jose Perez Bautista from Puebla state, was ordered released Thursday. He wasn't formally charged, but remains under investigation with his passport seized.

The main events at World Youth Day are a prayer vigil with the 84-year-old pope and outdoor sleepover for pilgrims Saturday night at a sprawling air base, and Mass there the next morning. Except for a trip Friday to a historic monastery in El Escorial, 30 miles (50 kilometers) northwest of Madrid, the pope will spend the whole four days in Madrid.

The visit promises to be a very special occasion for 103-year-old Cistercian nun Sister Teresita, who will leave her convent in the town of Buenafuente del Sistal, 110 miles (180 kilometers) north of Madrid, for the first time in 40 years to meet Benedict on Saturday.

“I haven't stopped talking on the phone since the news came out,'' convent mother superior Maria Romero said. She said Teresita is relaxed but does not like that the convent is becoming distracted by the event.

“Teresita says it's not a big deal and she has no desire to be a star,'' the mother superior said.

Teresa took her vows at 19 on April 16, 1927, the same day the pope was born. It was this coincidence that led to her receiving an invitation to leave the convent and meet him. April 16 is also the day of Saint Bernard, one of the founding members of the Cistercian order.

Superior Maria Romero described Teresita as “a simple person, hardworking and coherent. Very saintly.''