Obama rides wind of change to historic US victory

   * Democrats extend control of Congress

   * Jubilant supporters celebrate across country

   * Dollar rises, market reaction muted

   * World reaction mostly positive

   WASHINGTON, Nov 5 (Reuters) - Barack Obama rode a wave of  voter discontent to an historic White House victory, promising change as the first black U.S. president but facing enormous challenges from a deep economic crisis and two lingering wars.

   Obama led Democrats to a sweeping victory that expanded their majorities in both houses of Congress as Americans  emphatically rejected Republican President George W. Bush's

eight years of leadership.

   Raucous street celebrations erupted across the country, but Obama will have little time to enjoy the victory. He was expected to start work on Wednesday, planning his formal takeover on Jan. 20 and assembling a team to tackle the financial crisis and other challenges.

   Democrats gained at least five Senate seats and about 25 seats in the House of Representatives, giving them a commanding majority in Congress and strengthening Obama's hand. Four Senate seats remained undecided.

   The son of a black father from Kenya and white mother from Kansas, Obama was born when black Americans were still battling segregationist policies in the South. His triumph over

Republican rival John McCain on Tuesday is a milestone that could help the United States get beyond its long, brutal history of racism.

   "It's been a long time coming, but tonight, because of what we did on this day, at this defining moment, change has come to America," Obama, 47, told some 240,000 ecstatic supporters gathered in Chicago's Grant Park.

   Many world leaders welcomed Obama's victory and some hailed it as an opportunity to restore a tarnished U.S. image.

   "Your election has raised enormous hope in France, in Europe and beyond," French President Nicolas Sarkozy said. Newspaper headlines captured the momentous nature of the result. A New York Times banner headline said simply "OBAMA", while the Washington Post declared "Obama Makes History" and USA Today: "America makes history; Obama wins".

   Initial market reaction was muted. Analysts said Obama's victory had been largely priced in and concerns about the global economy were paramount, leading major U.S. stock index futures lower. The dollar moved higher, recovering some of the previous session's heavy losses.

OBAMA FACES BIG PRESSURES

   Obama won at least 349 Electoral College votes, based on  state voting, far more than the 270 he needed. With 96 percent of the popular vote counted, he led McCain by 52 percent to 46 percent.

   He will face intense pressure to deliver on his campaign promises. He has vowed to restore U.S. leadership in the world by working closely with foreign allies, to withdraw U.S. troops from Iraq in the first 16 months of his term and to bolster U.S. troop levels in Afghanistan.

   But his immediate task will be tackling the U.S. financial crisis, the worst since the Great Depression. Obama has proposed another stimulus package that could cost about $175 billion and include funding for infrastructure and another round of rebate checks.

   World leaders will gather in Washington on Nov. 15 for a summit on the global financial meltdown. The White House has said it did not expect the president-elect to attend, but Obama has not yet stated his plans.

   A first-term Illinois senator who will now be the 44th U.S. president, Obama said he would work to ease the country's sharp political divisions and listen to those who voted against him.

   "The road ahead will be long. Our climb will be steep. We may not get there in one year or even one term, but America,  I have never been more hopeful than I am tonight that we will get there," he said in Chicago.

   McCain, a 72-year-old Arizona senator and former Vietnam War prisoner, called Obama to congratulate him and praised his inspirational and precedent-shattering campaign.

   "I urge all Americans who supported me to join me in not just congratulating him but offering our next president our goodwill," McCain said.

ELATION IN THE STREETS

   Blacks and whites celebrated together in front of the White House to mark Obama's win and Bush's imminent departure. Cars jammed downtown Washington streets, with drivers honking their horns and leaning out their windows to cheer.

   Thousands more joined street celebrations in New York's Times Square and in cities and towns across the country.

   "This is the most significant political event of my generation," said Brett Schneider, 23, who was in the crowd for Obama's victory speech in Chicago.

   "This is a great night. This is an unbelievable night," said U.S. Rep. John Lewis of Georgia, who was brutally beaten by police in Selma, Alabama, during a civil rights march in the 1960s.

   Lewis was at a celebration in Ebenezer Baptist Church in Atlanta, the home church of Martin Luther King, who led the civil rights movement and was murdered in 1968.

   Allied governments said they hoped for closer cooperation with Washington, while critics of the United States, ranging from officials in Russia and Iran to Islamist groups in the Middle East, called for changes.

   "We hope that ... he adopts a just policy that restores to America its natural position of respect for humankind and democracy," said Mohamed Mahdi Akef, leader of the Egyptian

Muslim Brotherhood, one of the Middle East's largest Islamist groups.

   Russian Prime Minister Dmitry Medvedev spoke of hopes for

stronger U.S.-Russian relations, but at the same time vowed retaliation for a U.S missile-defense plan.

By John Whitesides, Political Correspondent - Reuters

FOREX-Dollar gains on risk aversion, Obama victory