The story is common amid the rapid economic development across much of Asia that has raised living standards for millions. But the relentless drive to build, modernize and emulate the West — combined with a mindset that equates the old with backwardness — has already consigned many traditional communities to rubble, and with them a way of life.
"There is more than just the architecture to preserve in the community. If these old buildings are demolished, the people will go. So will the lifestyle and culture. And that is irreplaceable," says Tiamsoon Sirisrisak, a researcher on culture at Bangkok's Mahidol University.
Authorities often say clearing old city quarters is justified because the structures are often decrepit and unsanitary. But while those who move may be pleased with more modern housing, running water, proper toilets and cleaner surroundings, they also often regret the loss of their old neighborhoods.
Rapid urbanization, weak legislation, corruption and even some religious beliefs have contributed to the trend. Most Asian cities have ignored recommendations to leave their traditional cores intact and bring modern development to outer areas, as many European cities have done.
—Old Phnom Penh survived war and the Khmer Rouge terror, but more than 40 percent of some 300 French colonial buildings that gave the Cambodian capital its unique character have been destroyed over the past two decades. In 2004, Prime Minister Hun Sen tore up a zoning law that had kept the city low and green, giving the go-ahead to erect high-rises anywhere in the capital. One of his ministers said tall buildings would attract tourists.
—In neighboring Vietnam, demolition of Rue Catinat, a street in the historic heart of Ho Chi Minh City, is proceeding block by block, driven as elsewhere by skyrocketing land prices. A Vietnamese-French urban research agency found that at least 207 heritage buildings have been destroyed or defaced in the last decade. The city's last colonial-era department store is to be replaced by a 40-story complex this year.
—Only slivers of an earlier Hong Kong remain, hemmed in by a dense cityscape. In a model that China itself has followed, Hong Kong's transformation was propelled by the former British government selling off land to developers who rooted out both the traditional Chinese quarters and the legacies of Imperial Britain.
Experts generally agree that China, which boasts the longest continuous architectural lineage in history, ranks first when it comes to wholesale eradication of material heritage. Raging against the feudal past, the Red Guards destroyed thousands of historic sites during the Cultural Revolution of the 1960s and '70s. In the economic boom that followed, the destruction continued if not intensified.
The flattening of historic cores of cities across China, from Kunming in the south to Kashgar in the far west, is Asia's greatest "cultural atrocity," said James Stent, an American involved in heritage preservation in China and Thailand.
The bulldozing of old Kashgar, a fabled way station along the Silk Road and one of the world's finest examples of a traditional Islamic city, began in 2009 and is all but complete. City authorities said the clearance was necessary because earthquakes could topple the old houses.
A 2011 survey revealed that 44,000 — or a fifth — of some 225,000 important cultural sites in China have fallen victim to construction. And a broader definition of cultural heritage that includes ordinary communities is new for many Asians.
"In China, they will preserve a temple but raze everything around it," Stent says. "You don't want little islands of culture, you need to protect larger areas and the whole fabric within them but make them vibrant so people can make a living there."
In Beijing, modern structures and roads have replaced some 60 percent of the city's inner core, with its narrow alleyways and traditional courtyard residences, says Matthew Hu, a leading Chinese conservationist who heads The Prince's Charity Foundation China.
"Modernity is really defined by modern Western culture, so when people consider modernity they want to get rid of things from the past," says Hu.
Although the scale and speed of this destruction appears greater than in Western countries, in many respects Asians are "simply mirroring similar dynamics from the West," that took place long ago, says Erica Avrami, director of research and education at the New York-based World Monuments Fund.
In New York, elegant homes and public buildings in midtown Manhattan were razed in the early 20th century. And in Europe, where many historic buildings were destroyed by bombs during World War II, researchers found that even more of them were leveled by bulldozers in the three decades that followed.
Asia's younger generation in particular seems uninterested in preservation.
In tropical Thailand, only palaces and religious structures were constructed of substantial materials and deemed worth of preserving, while domestic architecture, mostly of wood, deteriorated rapidly and is rarely renovated.
"The idea that you preserve the old wooden house of your grandfather or grand-grandfather is not in the Thai psyche," said Euayporn Kerdchouay of the Siam Society.
Scholars note that a basic Buddhist tenet views the world as a place of constant change, and thus the faithful tend to downgrade the notion of permanence. Many Buddhists believe donating to build a new pagoda or shrine will earn them greater merit than renovating old ones.
In Bangkok's Chinatown, 40 old shop houses have been torn down to make room for a subway station intended to ease traffic. Structures up to 12 stories high will rise in their place.
Sirinee Urunanont, a third-generation Chinatown resident and community leader, says Chinese media have come to film and report on traditions and lifestyles that don't exist in their country anymore. Her quarter, Charoen Chai, is famed for handcrafted joss paper products used in festivals and funerals. These include replicas of gold bars, limousines and other creature comforts to accompany the dead into the next world.
"The culture, traditions, you don't see them anymore. They have been lost. So the Chinese media comes here to see them," said Sirinee.
Some excellent examples of preservation do exist, often driven by tourism. These include the 17th century "machiya" townhouses in Japan's ancient capital of Kyoto, Beijing's The Temple Hotel, an award-winning, four-year restoration effort, and the campaign to save the British colonial buildings of Yangon, Myanmar.
But even some success stories have downsides. Malaysia's George Town was named a UNESCO World Heritage Site in 2008 for its blend of Asian and colonial architecture, and tourists flocked in and probably saved it from demolition. But longtime tenants were replaced by boutique hotels, cafes and restaurants, and the population dropped from 50,000 to less than 10,000.
"People don't understand that the inner-city residents have kept our traditions alive," says Khoo Salma, a leading Malaysian conservationist. "This has happened to many world heritage sites, where they have become a playground for others and no longer the people's city. We don't want the soul of (our) city to die."