Slums have historically been seen as sordid, degenerate urban worlds in which poverty and crime are rife. Even the word itself evokes negativity.
"Its derivation may be from 'slump', meaning 'swamp', or it may be a fortuitous blend of 'slop' and 'scum'," observed the late American urban planner Charles Abrams.
"It also carries with it the cadence of 'slob', 'slush', 'slovenly', 'slut', and other derivatives of the sl combination.
"Slum reveals its meaning the moment it is uttered."
The word, which emerged in London cockney slang, originally denoted low backrooms and streets where disreputable things happened, but was gradually been applied to larger and larger urban areas.
For Alan Mayne, the author of Slums: A History of Global Injustice, it tells us far more about the fantasies and anxieties of its users than it does about the communities it often misrepresents.
"Usage of the word 'slums' is profoundly deceitful; it's a word that has been used by powerful groups to stereotype, marginalise and disempower society's least powerful groups," says Dr Mayne, an adjunct professor at the University of South Australia.
"It is a word that has profoundly misshaped public knowledge and skewed public policy for the best part of two centuries."
Wiping slums from the map
Crucially, according to Dr Mayne, the word has been used to rationalise a series of state and non-state interventions in the name of reform.
In 2000, the United Nations' Millennium Declaration drew global attention to the "abject and dehumanising conditions of extreme poverty", in which over a billion people lived.
The slogan adopted was "cities without slums" — and with it came a promise to improve the lives of at least 100 million slum-dwellers.
This improvement, Dr Mayne says, took the form of "upgrading" projects, which often led to displacement and forced evictions, and rarely involved consultation with local communities.
"Because the word 'slums' still permeates thinking and the language of reform, the effect is to marginalise communities from the decision-making process," he says.
"Experts make decisions for the poor, [and] the poor aren't actively engaged in the dialogue that shapes policy."
The UN's intervention was, however, only one of the latest in a series of attempts to eradicate what has long been seen as a blight on the modern metropolis.
"In Britain, where the war on slums had been pursued with the greatest vigour, some 2 million homes, accommodating 5 million people, were demolished between the 1930s and the 1970s," Dr Mayne says.
"In the United States, renewal projects sanctioned under the pivotal Housing Act of 1949 had by the mid-1960s targeted over 400,000 blighted housing units."
To planners, slums represent a failure of the project of modernity, a glaring embodiment of profound social inequality at the heart of our modern cities.
And so the history of slum clearance projects is, according to Dr Mayne, a turning away from the contradictions and injustices of contemporary urban life.
In one of the starkest attempts to banish slums from collective consciousness, Dr Mayne cites the response of Brazilian authorities to increased international attention in the lead-up to the World Cup and the 2016 Olympic games.
In 2011, city officials complained that Google Maps "gave too much prominence to favelas".
"Google responded that the company had never intended to 'defame Rio' and that its map labelling would be changed," Professor Mayne says.
And so Brazil's slums were — quite literally — wiped off the map.
Another danger? Exoticising poverty
Dr Mayne argues that one of the most damaging effects of the word slum is the representation of slum-dwellers as deviant, degenerate, disordered and disaffected.
Another is the failure to recognise the internal dynamics of these communities, and the existence of complex and vital forms of social life.
"Behind the distorting stereotypes of environmental chaos and psychological upheaval, there are informal worlds, informal societies, informal economies, which are vibrant and enduring and accumulating," he says.
But he also points to the danger in seeking to celebrate the "vibrancy" of society's most deprived communities — an exercise all too common among Western travellers, who exoticise the material deprivation of slum communities.
Likewise, Dr Mayne admits there is a risk that in seeking to emphasise the agency of slum-dwellers, their stories might be co-opted to legitimise a moral and economic argument, one that says entrenched poverty can be overcome with an entrepreneurial spirit and individual hard work.
"There is a risk, of course, in attempting to redress outsider bias and to reclaim slums as 'normal' communities, of artificially smoothing over the trauma and danger of living in poverty," he says.
"Happy families and supportive neighbours do not altogether compensate for the sharp-edged realities of inequality.
"We are talking about people whose life chances are severely circumscribed. But these are people who nonetheless can build lives and livelihoods for themselves, for their neighbourhoods and for their communities."