Responsible for powering the country and its economy, the U.S. energy grid has come under increasing strain due to climate change, and the threat of cyberattacks looms.  

Boko Haram, known for mass kidnappings, bombings, and other acts of terrorism, remains an enduring threat to northern Nigeria and the Lake Chad Basin.

The world is inching closer to eradicating polio, but armed conflicts and opposition to vaccines stand in the way of finally eliminating the disease.

Tariffs have been applied over the years to protect homegrown industries and target competitors who are seen as using unfair trade practices. They impose costs on both importers and exporters and had been in decline until the recent U.S.-China trade war.