Ecologist Sergey Zimov has created Pleistocene Park, a 14,000-hectare experiment testing whether hairy beasts can bring back ancient grasslands and prevent carbon-rich permafrost from thawing.
A father-son team in Siberia wants to bring millions of animals to the tundra to preserve the permafrost, which has more than a trillion tons of carbon frozen in the soil.
The indigenous tribes emerging from Peru's jungles fear for their lands and livelihoods. Without government protection, they may not be able to survive.
In Tijuana, ending AIDS seems a distant goal. The area lacks the necessary leadership and resources to fight the virus.
A growing number of locales have become convinced that they have the tools to halt their AIDS epidemics. But in others, a vast distance separates the dream from the reality.
Heather Pringle explains the history of contact between European and indigenous Mexicans, Central Americans, and South Americans, tracking the historical spread of disease and warfare.
As Peru's indigenous peoples make themselves increasingly visible, locals attempt to understand these neighbors, and activists and governments take steps to prevent the spread of disease or hostility.
In the 1950s, a visit by a single outsider sickened a band of tribespeople.
As encounters with indigenous Amazonian peoples in Brazil grow more frequent, Brazil's National Indian Foundation (FUNAI) and the Brazilian Government work to ensure these groups' survival and health.
Brazil's former "attraction fronts" initiated contact with indigenous tribes like the Nambikwara, but anthropologists today describe this tactic as genocide.
Local religious and political leaders in Puerto Esperanza, Peru, advocate for the construction of a road connecting the town to more populated areas. Many environmentalists oppose them.