Bono and U2 rocked more than 80,000 fans in Dublin as the Irish supergroup's latest world tour hit new emotional highs Friday night on home soil. A deafening roar welcomed the Dubliners as they launched their three-concert homestand at Croke Park, Ireland's biggest stadium and a cathedral to Irish nationalism. The band's '360' tour -- featuring its underselling 12th studio album, 'No Line on the Horizon' -- switches from Europe to North America in September. 'We are so young -- as a nation!' shouted the 49-year-old lead singer Bono. Crowds braced for downpours threw their raincoats aside as an unexpected sunset gave way to a starry Dublin night. All of the '360' concerts feature a stunning feat of engineering: the four-taloned 'Claw' stage. The 390-ton, green cabana stands more than 10 stories above the band as they strut through the crowds on moving bridges and a ring-shaped stage with concertgoers inside and out. The U2 touring juggernaut deploys three 'Claws' -- each costing euro100 million ($140 million) and capable of holding up more than 150 tons of lighting, pyrotechnics and giant TV screens -- that are continually being assembled and disassembled in different concert locations. Before taking the stage, Bono joked that the band's performances in Barcelona, Milan, Paris, Nice, Berlin and Amsterdam were just 'rehearsals' for the Dublin concerts. And in front of a crowd waving flags from as far away as Brazil and Japan, Bono said tens of thousands had traveled worldwide to Dublin. 'You know the best place to see U2 live is right here,' he said to cheers. The U2 gigs are delivering an estimated euro50 million ($70 million) boost to Ireland's recession-ravaged economy, with most Dublin hotels booked solid for weeks. Even the Dublin Criminal Court shut down jury deliberations for the weekend because too many jurors had U2 tickets. Nonetheless, Ireland's descent into double-digit unemployment could be seen in the stands. Several thousand seats remained empty -- the first non-sellout of a U2 gig in Dublin since 1980. Irish safety laws also barred fans from the most hallowed end of Croke Park: standing-room-only concrete stands called Hill 16. Hill 16 was built on rubble from Ireland's first, failed rebellion against British rule in 1916. Ireland won independence six years later, but not before British security forces made Hill 16 the most infamous killing ground of the conflict, shooting to death a dozen spectators and athletes at a Gaelic football match. The day become known as Ireland's first Bloody Sunday, the inspiration for U2's 1983 anti-war anthem 'Sunday Bloody Sunday.' 'We're undefeatable!' Bono shouted. 'Hill 16 right behind us. Out of the rubble of a revolution in 1916 they built a beautiful stadium, and more importantly they built a great country. And there is nothing we can't do if we believe in ourselves.' High school students Paul 'Bono' Hewson, guitarist Dave 'The Edge' Evans, drummer Larry Mullen and bassist Adam Clayton came together to form U2 in Dublin 33 years ago. ------ On the Net: U2, http://www.u2.com 