Brazil, Russia, India and China, the so-called Brics, are predicted to emerge as major world players by 2050. In this, the first of a four-part World Service series called Brics: The Changing Face of Global Power, the BBC's Peter Day examines how the tables are turning.
Are the US, Europe and Japan ageing powers? Are they about to be overtaken by vigorous new players - countries once dismissed by Western analysts as Third World nations?
Brazil is emerging as a global heavyweight thanks to solid growth
A report by giant investment bank Goldman Sachs argues that by 2050 only the US and Japan are likely to remain in the G7, the group of the world's seven richest nations.
Replacing the UK, Germany, Italy and France, says Goldman Sachs global economist Jim O'Neill, will be Brazil, Russia, India and China - the "Brics".
"Well, China has just in the past couple of years, as people probably know, overtaken Italy," he says.
"And it's sitting just behind France and the UK. But that is nothing compared with what we're about to see unfold over the next 20-plus years."
If Goldman Sachs' sums are right, the Brics should be able to seize "enormous opportunities" in consumer goods industries during this period.
Daslu, a high-end luxury mall in Brazil's business capital Sao Paulo, is where the elites come to spend their money.
Among other extravagances, the exclusive department store boasts shopping assistants standing by to escort high-spending clients into a discreet world of luxury.
China's hunger for raw materials has injected huge sums of money into Brazil in recent years - and some of it is clearly being spent here, just a few hundred yards from one of the city's infamous favelas, or slums.
Despite the rapid advances, Patricia Ramalho, a Daslu publicity manager, is surprisingly frank about Brazil's poverty and social problems.
"If you come to Brazil, you realise that there are two Brazils," she says.
"I wouldn't say only rich Brazil and poor Brazil, but I would tell you serious Brazil, private Brazil - and public Brazil."
In fact, the Brics have a vast chasm to bridge. With a total of 2.7 billion people, they make up roughly half the world's population.
Yet wealth levels in Brazil and Russia are barely one-tenth the level in countries such as the US and Japan. China and India are even poorer than the other two Brics.
Will they really be able to attain new wealth and power by 2050?
Indian-born management guru CK Prahalad, author of The Fortune at the Bottom of the Pyramid, argues that it will happen much sooner.
They will be major economic powers well before 2050, he says - and much of that growth will be powered by people now considered to be poor.
"The growth engines are starting from ground up," he says. "I always say: build it for the poor; the rich will come."
Brazilian economist Roberto Zagha, an adviser to the World Bank's Poverty Reduction network, believes people are unaware how the development of the developing world will affect the industrialised world.
He argues the impact of economic development will mean there will be poor and low-income groups in industrialised countries, in the same way as there are lagging regions in developing countries.
"So there will be a blurring of being developed and developing, and there will be much more contrast, diffused contrast, in the same country," he says.
A former Reagan administration trade official, Clyde Prestowitz, says global institutions will have to change to reflect the new economic distribution of power.
"The World Bank and the International Monetary Fund - all the voting weights in all of these are all going to change.
"The Brics are going to have more weight.
"It doesn't mean that they're going to be exclusive; it doesn't mean that they're going to dictate things - but we're not going to dictate things.
"That's going to be the big change: we're not going to dictate things."
Just as the end of communism changed the shape of a world we had been familiar with, so the likely - maybe inevitable - rise of the Brics nations will redraw the map of global power.