Cheap, quick and tasty, fast food became a culinary craze in the 1950s. But has our quest for convenience created an irreversible health crisis?

Fifteen international agencies spend $62 billion every year on space travel. What's fueling our costly — and dangerous — drive to explore the universe?

In the 21st century, China has become a global economic powerhouse. Why was the rest of the world so slow to notice its rise to the top?

Plastics have transformed how we live, but progress comes at a high price: 7.8 billion tons of waste. Are plastics a miracle or a catastrophe?

Oil has brought great wealth to the Middle East and ignited major wars. Is it a blessing or a curse for the region, as well as the rest of the world?

Feminism has ushered in sweeping changes to society, securing rights for women around the world. How much further do we have to go?

Over 10% of the world's electricity comes from nuclear power. But with radioactive waste and the threat of nuclear meltdown, are we playing with fire?

Nearly 40 million people are living with HIV. After decades of research and activism, how far have we come in finding a cure and battling the stigma?

DNA analysis has given us the tools to map disease, solve crimes and more. But in our rush to decode DNA, are we leaping before we look?