Ecologists sounded the alarm. The Amazon rainforest is disappearing at the fastest rate in nearly a decade. But the outcry left many Brazilians suspicious.
They say the protesters don't really care about saving the world's largest wilderness -- they want to steal it from Brazil.
Sprawling over 4.1 million km2, the Amazon covers nearly 60 percent of Brazil. Largely unexplored, it contains one-fifth of the world's fresh water, oil, diamonds, gold and untold other mineral and biological riches.
Last year, the Brazilian Amazon lost an area of 26,130km2 of rainforest, an area slightly smaller than Belgium. Environmentalists estimate as much as 20 percent of the jungle has already been cut down by ranchers, loggers, farmers and developers.
But the idea that the Amazon is important for the world's climate, its biodiversity and a global heritage is seen as a smoke screen -- the rainforest belongs to Brazil, and anyone who says differently has ulterior motives.
"I am also convinced that the international attention to the recent news of deforestation has much more to do with the internationalization of the Amazon than with preservation of the rainforest," General Claudio Barbosa de Figueiredo, head of the Brazilian military's Amazon Military Command, said at a seminar entitled, "The Amazon Brazilians Don't Know."
To outsiders, fear of an invasion by a more powerful country such as the US seems farfetched. Indeed, in other countries that have Amazon rainforest within their borders -- Colombia, Venezuela, Peru, Ecuador, Suriname and French and British Guyana -- people tend to fear more that Brazil will try to seize the entire rainforest.
But in Brazil, a recent poll sponsored by Renctas, a group that combats animal trafficking, found that 75 percent of the people believe their country runs a real risk of being invaded by a foreign power that covets the country's vast natural riches.
"The strategic axis of confrontation has shifted from East-West to North-South," Figueiredo said. "In other words, the rich countries of the North are confronting the countries that want to develop in the South to impede this in every possible way."
Figueiredo explained that Brazil's generals have developed a strategy of "resistance" to deter a superior military power by employing guerrilla tactics in the Amazon.
"There are military planners seriously engaged in this policy of resistance. When I ask them who the superior power might be, they say `the United States' or `the G-8,'" said Celso Castro, a history professor at the Getulio Vargas Foundation, at a seminar. "Most of my students believe foreign invasion is a real threat, too."
In recent years, the government has spent US$1.4 billion on a sophisticated radar system to monitor air traffic over the Amazon region and has bulked up troop strength along its porous jungle borders.
The conspiracy theorists say groups defending the environment or Indian rights are merely fronts for interests to steal the region's riches and undermine national sovereignty. Foreign military aircraft cruising in or near Brazilian airspace are said to be attempting to map the region's vast mineral wealth.
Many Brazilians believe that grade school children in the US are taught the Amazon is part of an "international reserve."
"That's what people are raised to believe here. Most people believe in one form or another that foreigners want to steal the rainforest," said Philip Fearnside, a research professor for 29 years at the National Institute for Research of the Amazon, in the jungle city of Manaus.
"There's a lot of suspicion of science or money coming from outside," Fearnside said. "It affects conservation. It prevents a lot of things from happening that might be done."
Despite great expectations for the rainforest, it remains mostly empty. The Amazon is home to only about 10 million of Brazil's 183 million people -- most Brazilians live far away, in the big cities of the south and the Atlantic coast.
For years, foreigners have tried and failed to strike it rich in what Brazilians often call the "green hell."
In the 1920s and 1930s, US tycoon Henry Ford spent US$20 million on a massive project to harvest rubber, only to see it fail when the trees were ravaged by leaf blight.
In the 1980s, automaker Volkswagen undertook a project for large-scale cattle ranching in Para state. It also failed, despite billions of dollars in tax breaks, because of high operating costs and poor infrastructure.
Perhaps the most ambitious project was conceived by US billionaire Daniel K. Ludwig, who shipped a floating pulp mill and a factory all the way from Japan -- only to discover that the jungle was inhospitable to the huge monoculture of gmelina trees planted to produce high-quality paper.
Ludwig turned the project over to a Brazilian consortium in 1981, which paid nothing but assumed the project's massive debt.
Today the Amazon is being invaded by soybeans. Environmentalists say soybean farming has driven up the price of deforested land, encouraging cattle ranchers to sell their pastures and head deeper into the jungle, clearing forest and selling the wood to loggers.
But Brazilian businessmen backing the soy expansion blame criticism on outside meddling.
"Behind the environmental concerns are economic interests. They are trying to impede or slow the growth of Brazilian production," Mato Grosso state Governor Blairo Maggi -- who is also one of the world's largest soybean producers -- said in 2003.
Albert Fishlow, director of the Institute for Latin American Studies at Columbia University in New York, said that although the Amazon remains desperately poor, Brazilians still see it as the land where millions of dollars can be made and live in fear that someone other than Brazil will get that money.
Fishlow called the theory of a foreign conspiracy politically convenient.
"These kinds of things have a way of emerging exactly when there's a frustration," he said. "It lets people focus, lets them see that Brazil is being saved from the rest of the world."