Hundreds of thousands of young pilgrims have given Pope Benedict XVI a rapturous reception as he presided over a lavish ceremony during Catholic festivities in a sweltering Madrid.
Thursday's adoring welcome was in sharp contrast to scenes nearby, where baton-wielding Spanish anti-riot police dispersed about 150 anti-pope protesters who had gathered in the capital's Puerta del Sol square.
It was the second night of clashes in the square between police and activists furious over the high cost of the visit and the six-day million-strong World Youth Day festival amid tough economic times in Spain.
Police also peacefully dispersed gays and lesbians who attempted to stage a mass kiss-in on Benedict's route through Madrid.
Wearing a white cassock with a gold and crimson stole draped around his neck and a white skullcap on his head, the pope sat on a giant white throne on the stage in Madrid's emblematic Plaza Cibeles square.
The 84-year-old pontiff was shielded from the August sun by a giant white umbrella and cooled by water vapour descending from above the stage, which was adorned with a giant image of Mary and Jesus.
A sea of pilgrims, most wearing the yellow T-shirts and sunhats of the festival, packed the square and surrounding avenues for the evening ceremony.
Christians from the five continents presented him with traditional gifts on stage: from bread and salt from a Polish woman to Pacific island flowers from a young Australian man.
The leader of the world's estimated 1.2 billion Roman Catholics arrived in Madrid Thursday to lead the rock-festival style celebration, which lasts until Sunday and which organisers say has drawn faithful from 193 nations.
Benedict was earlier handed the keys to the city by the mayor of Madrid, Alberto Ruiz-Gallardon.
He then walked through the majestic archway of Puerta de Alcala, one of the five historic gateways to the city, accompanied by 50 young pilgrims -- 10 from each of the five continents.
He was presented with a small olive tree and treated to a equestrian dressage show by riders in traditional Spanish costumes, before continuing on in the popemobile to the Plaza Cibeles for the welcoming ceremony.
In his address to the faithful, the pontiff appealed to them to resist the temptation to follow "fashionable ideas."
"To all those who are content to follow fashionable ideas, they take shelter in the here and now, forgetting true justice, or they take refuge in their own opinions instead of seeking the simple truth.
The pope on Friday evening will preside over a 700-metre (nearly half-mile) Stations of the Cross service, in which representatives from 15 nations will participate, covering a route representing the steps in Jesus' crucifixion and resurrection.
He will also travel to the monastery of El Escorial outside Madrid to meet with around 1,000 college professors. The pontiff is also due to meet King Juan Carlos as well as Prime Minister Jose Luis Rodriguez Zapatero.
The party atmosphere at the start of the papal visit was shattered when police baton-charged about 150 protesters in the Puerta del Sol square.
Police had earlier blocked off the square and used vans to hem in the demonstrators, and called on them to leave before striking them on the legs to disperse them.
"They (the police) hit me five or six times. We came unarmed, we did nothing, we were here for a public demonstration," said Bruno, 30, who had blood on his elbow.
Protesters -- including some priests -- are fuming over the official 50.5-million-euro ($73 million) price tag, excluding the cost of police and security, of the August 16-21 celebrations.
Nationwide unemployment stands at more than 20 percent while youth unemployment is running at more than 45 percent.
In a speech at the airport, the pope voiced sympathy with the unemployed, saying "many young people look worriedly to the future, as they search for work, or because they have lost their job or because the one they have is precarious or uncertain."
Spanish police also foiled plans by 100 gays and lesbians to stage a kiss-in on the route the pope took through Madrid Thursday evening, blocking the protesters before they could meet up.
Only two men managed to skirt the security clampdown and kiss for the cameras just as the pope passed by along the major Madrid artery of Calle Serrano.