Royal Dutch Shell, in order to settle several lawsuits brought in a U.S. court, agreed Monday to pay $15.5 million to the families of Nigerian protesters executed by the military regime in the 1990s.

The Anglo-Dutch oil firm, which abandoned its oil fields in Ogoniland in Nigeria's Niger Delta in 1993 due to protests, said it played no part in the violence.

Although polio has been wiped out in most of the world, it is a growing problem in Nigeria. NewsHour special correspondent Fred de Sam Lazaro reports on efforts to fight the disease.

A swath of northern, predominantly Muslim states in Nigeria adopted hard-line Islamic law, sparking clashes among residents and posing problems for the government.

Following Nigeria's independence from Britain in 1960, the country's political life has been marked by cycles of corruption, instability and military coups. Read about Nigeria's leaders here.