Thirty-one years have passed since the fall of Saigon brought an ignominious end to the Vietnam War. The last US troops had left two years earlier. Yet it continues to haunt the American psyche, especially today, when so many parallels can be drawn with the current situation in Iraq.
Images of Vietnam remain profoundly influenced by the war: forests defoliated by Agent Orange; the massacre at My Lai; B-52 bombers dropping their deadly load; people fighting to board a helicopter as it takes off from the roof of the US embassy; a little girl runing in terror, her body scorched by napalm.
But while reminders of that conflict are still visible, modern Vietnam is very different from the place abandoned to the Viet-cong in 1975 - as President George Bush is set to discover this Friday when he arrives for the Asia-Pacific summit. It is a country of elegant colonial-era hotels restored to five-star luxury, restaurants offering the best of Asian and French cuisine, golf courses, and upmarket shops rivalling those of Singapore and Hong Kong.
The Vietnamese economy - devastated by decades of fighting, the destruction of much of the infrastructure and the dead hand of communism - is booming, fuelled to a large degree by tourism. A country that was once a byword for death and devastation is now a chic travel destination, and a must-do stop on the backpacker trail.
America - which lifted its trade embargo, in place since the war, in 1994 - has become Vietnam's biggest trading partner. Vietnam exports about $7bn (£3.7bn) worth of goods to its former enemy every year. Business travellers marvel at the gleaming new hotels and office blocks springing up in Hanoi and Ho Chi Minh City - the motorbike-choked southern metropolis still called Saigon by the locals.
The Apec (Asia-Pacific Economic Co-operation) summit, which will take place in Hanoi this weekend, is the biggest event that Vietnam has hosted. Officials are looking forward to showing off their graceful northern city, which is known as "the Paris of the East", with its lakes and parks and wide boulevards.
Heads of state and senior ministers from 21 member countries - including Japan's new Prime Minister, Shinzo Abe, and Condoleezza Rice, the US Secretary of State, who arrives in Vietnam tomorrow - will attend the annual summit.
George Bush will be the second US president to visit Vietnam, following a trail blazed by Bill Clinton in 2000. Full diplomatic relations had been restored in 1995. But it was the visit of the Vietnamese Prime Minister, Phan Van Khai, to the White House last year that really seemed to confirm the burial of the past. He was the first Vietnamese leader to set foot on US soil since the American War, as they call it in Vietnam. As well as Mr Bush, he met business leaders including the chairman of Microsoft, Bill Gates.
In June this year, he and President Tran Duc Luong resigned, to be replaced by two younger men, President Nguyen Minh Triet and Prime Minister Nguyen Tan Dung. The pair had been in power for nearly a decade, and the changing of the guard was seen as a further sign of Vietnam's focus on the future, rather than the past.
The country has undergone two decades of economic liberalisation, or doi moi ("renovation"). The process was slow for a long time, but accelerated in recent years, and Vietnam is now the fastest-growing economy in south-east Asia, and the newest member of the World Trade Organisation.
As if further proof was needed that Vietnam has adopted modern values, the country was rocked by a corruption scandal earlier this year, with the Transport Minister, Dao Dinh Binh, forced to resign amid allegations of millions of dollars of public money embezzled by his staff. Ministry officials were accused of using funds from construction projects and bribes to bet on football matches.
Tourism took off in the 1990s, with Vietnam marketing itself as a destination offering history, culture and modern facilities, not to mention an array of beautiful beaches. Visitors were attracted by the idea of a place that was a bit different and a bit gritty, although in reality it was an easy country to travel in, full of welcoming people.
Since 11 September 2001, the country has had the added appeal of being one of the world's dwindling collection of "safe" places. Australians who no longer feel secure in Bali, for instance, following two terrorist bomb attacks, are flocking to Vietnam in ever-growing numbers. Long-haul travellers between Europe and Australasia are choosing to stop over there, sometimes combining it with a side-trip to neighbouring Cambodia or Laos.
But despite its wholehearted embrace of capitalism, and the way it has opened itself up to the outside world, Vietnam - one of the few communist countries left - remains an authoritarian one-party state. Political opposition is not brooked, and dissidents are harassed and detained. Pluralism, democracy, freedom of speech, and freedom of religion are alien concepts. Hundreds of political and religious dissidents languish in jail.
While America remains bruised by the loss of 58,000 service personnel in Vietnam, the war claimed a staggering 1.3 million Vietnamese lives. And once it was over, with the country reunified and a communist leadership installed, the people's suffering did not end. Vietnam invaded Cambodia, where it overthrew Pol Pot and his Chinese-backed Khmer Rouge regime, and troops also defended Vietnam's northern border against a Chinese invasion. The legacy of the Vietnam War lingers on, too. Visitors are struck by the number of people with missing limbs. Since the war ended, an estimated 10,000 Vietnamese have been killed or maimed by landmines.
And, more than 30 years after the end of the war, children continue to be born with terrible deformities, the legacy of Agent Orange and other chemical defoliants that were sprayed from the air to destroy the jungle hide-outs of Vietcong guerrillas.
The Vietnamese government estimates that half a million children have been born with congenital defects, and that two million have suffered cancers and other ill effects. At the Tu Du maternity hospital in south Vietnam, an entire wing is filled with severely affected babies who have been abandoned by their parents. Unlike American war veterans, the victims of Agent Orange have never received compensation. US servicemen who came into contact with the chemical, which contained dioxin, received a multimillion-dollar settlement after suing the manufacturers in 1984.
A report published earlier this year, meanwhile, found that much of the environmental damage caused by the defoliants has not been repaired. An estimated 20 million gallons of chemicals were dumped on Vietnam's forests by the Americans between 1961 and 1971.
For many tourists, the reminders of the war are a draw, providing an extra frisson to a holiday mainly spent exploring Vietnam's cities and relaxing on its beaches. At Saigon's markets, there is a roaring trade in war memorabilia, some authentic, much of it not. Hawkers jostle to sell foreigners the dog-tags and Zippo lighters that supposedly belonged to American pilots. Tour companies offer trips to the former Demilitarised Zone, and the opportunity to walk part of the Ho Chi Minh trail - a web of dirt roads and footpaths carved out of the Truong Son mountain range to facilitate the movement of soldiers and supplies from North Vietnam to the battlefields of the south.
At Danang, the beachside town where American troops went for rest and recreation, children offer tourists copies of Graham Greene's The Quiet American, the novel that was made into a film starring Michael Caine, set in Saigon during the French Indochina war.
Earlier films such as The Deerhunter and Apocalypse Now, about the subsequent American war, helped to crystallise the outside world's image of Vietnam. But the French influence remains strong, too. Older people still speak fluent French. Roadside stalls offer baguettes and good strong coffee.
More than half of Vietnam's population is under 30, with no memory of the horrors of war. For young people, particularly members of the emerging middle class, new cars and designer labels are the status symbols of choice. Sadly, there is also a thriving trade in child prostitution. A sizeable proportion of visitors are child sex tourists.
A brief history of the Land of the Blue Dragon
After years of intermittent rule by Chinese dynasties, Vietnam - often called the Land of the Blue Dragon - achieves independence in the 10th century. In the 19th century, it becomes part of French Indochina, but is occupied by Japan during the Second World War. When war ends, the battle for independence from France begins.
France withdraws troops after a major defeat at Battle of Dien Bien Phu during the First Indochina War. Country is divided at 17th parallel into North Vietnam and South Vietnam - a division intended to be temporary. But communist forces gain control of the North and civil war becomes a part of Washington's global campaign against communism. The US enters hostilities to stem "domino effect" of successive nations falling to communism.
US forces become embroiled in vicious guerrilla war with the Vietcong, the South Vietnamese communist militia. Massacre of hundreds of civilians by US troops in the village of My Lai proves a turning point in domestic support and provokes international outrage.
As casualties mount, and conflict spreads into neighbouring Laos and Cambodia, Washington starts transferring combat roles to the South Vietnamese military.
The Paris Peace Accords of 27 January 1973 formally recognise sovereignty of both sides. All US combat troops are withdrawn by 29 March 1973. The North again invades and overpowers the South in 1975 and on 2 July 1976, South Vietnam is officially reunified with the North as the Socialist Republic of Vietnam . War has left the country devastated - economically, socially and politically - and between one and two million people, known as "boat people" flee by sea. Many drown, or are murdered by pirates.
After a decade of communist policies, Vietnam experiments with free-market economics, and becomes one of world's fastest-growing economies. But despite extensive reforms the Communist Party maintains its grip on society.
Vietnam normalises relations with United States. The country has set its sights on becoming a developed nation by 2020.