Democrat Barack Hussein Obama has been elected the first African-American president of the United States in a contest that shattered racial barriers.
With polls now closed, the 47-year-old first-term senator from Illinois has captured the key states of Florida, Ohio, Pennsylvania, Colorado and California.
Those wins, combined with a slew of other states, have given him 338 electoral votes so far, more than enough to defeat Republican rival John McCain.
Swiss President Pascal Couchepin hailed Obama's win as "the choice of the future".
"America has shown it is capable of opening new frontiers," he said.
Foreign Minister Micheline Calmy-Rey also welcomed the news, saying Obama "speaks like we do".
"[He] speaks of dialogue, human rights and climate change," she said. "He transcends the past drama of racism in the United States."
In a victory speech before a crowd of about 125,000 supporters in Chicago, Obama pledged to restore the country's standing in the world, tackle the financial crisis and reunite a population divided under George W. Bush.
"We rise or fall as one nation, as one people," he said in words reminiscent of civil rights leader Martin Luther King. "A new dawn of American leadership is at hand."
America's might, he said, did not come from the power of its military or the amount of its wealth but from the quality of its ideals – liberty, democracy and opportunity.
McCain, burdened with the baggage of a deeply unpopular president, could not overcome pollsters' predictions that the country had tipped decidedly toward his Democratic opponent.
As he lost New Hampshire, Virginia, Ohio and Pennsylvania – states where McCain had pinned his hopes – an Obama victory seemed unavoidable.
"I pledge to him tonight to do all in my power to help him lead us through the many challenges we face," McCain conceded in his home state of Arizona.
"Today I was a candidate for the highest office in the country I love so much, and tonight, I remain her servant."
Bush also called Obama to congratulate him and invite him to the White House.
Throughout the country as precincts closed and a Democrat victory seemed at hand, Americans rolled into the streets waving flags and chanting "Yes, we can", a refrain from the Obama campaign that hinged on a message of hope and change.
Record numbers turned out for the election, with an estimated 130 million people going to the polls. Queues were so long in some places that Americans waited as long as 4.5 hours to vote.
Early analyses showed that the 2008 election had produced a surge of first-time voters. Pro-Obama volunteers spent months helping hundreds of thousands of young voters register.
Results early on Wednesday morning showed 68 per cent of voters under 30 years old had voted for Obama. Senior citizens were the only clear age group that preferred McCain, the data indicated.
Blue and green
The Democratic sweep spilled into Congress as well, where Democrats now have control of both the Senate and the House of Representatives. That has not happened since Bill Clinton was elected president in 1995.
Even so, with military operations in Iraq, an economy in shambles and the likelihood of a long recession, the Obama administration faces enormous challenges in fulfilling promises to cut taxes, bring troops home and improve health care.
Obama is expected to begin filling White House positions as early as this week, although he will officially take office on January 20, 2009.
The campaign, which lasted roughly two years, was one of the longest in the country's history. It was also the most expensive. Obama, who mobilised a massive fundraising and voter registration network, raised $639 million (SFr747 million) compared with McCain's $335.3 million.
In 1996 entire spending between both parties amounted to $478 million.
swissinfo with agencies
Stock market reaction
European shares ended lower on Wednesday. The Swiss Market Index of Switzerland's 20 leading companies finished 3.48% lower than at Tuesday's close on 6177.15 points.
Elsewhere, Britain's FTSE 100 index was down 2.3%, Germany's DAX was 2.1% lower and France's CAC 40 was down nearly 2%.
Switzerland on Obama's black list
President-elect Barack Obama and two other senators are behind a draft law called the "Stop Tax Haven Abuse Act", a 68-page document that blacklists Switzerland and more than 30 other countries.
The plans foresee widening the powers of the US economic and finance ministries as well as the Internal Revenue Service (IRS) to investigate and punish tax evasion from countries the US considers tax havens.
One of the sanctions in the text would prohibit all foreign banks involved in tax evasion from introducing credit cards on the US market.
The text includes a list of 34 countries, including Switzerland, which are considered as "probable tax evasion locations" in the eyes of the IRS.