AIDS is now second only to the Black Death as the largest epidemic in history. AIDS kills roughly a million people a year, or about one person every 30 seconds, as you can see here. This death toll surprisingly includes a lot of children, who are often infected with the HIV virus during pregnancy or through breast-feeding.

The toll is worst in Africa, where millions of parents have died, leaving children as orphans. Often teachers have died as well, leaving schools empty. Doctors and nurses have died, leaving hospitals and medical clinics with nothing. Farmers have died, leaving crops in the fields. Entire villages have been devastated.

Yet AIDS is a preventable and increasingly treatable disease. The huge majority of deaths can be stopped. Through education, the use of condoms, and proper medicine, AIDS has been brought under control in the developed countries. The same can be true in Africa and other parts of the world.

Sources: Joint United Nations Program on HIV/AIDS (UNAIDS), World Health Organization (WHO).

Note: The map display above is representational only and does not show the names and faces of real people. The photographs are computer composites of multiple individuals.