In this issue:
"Memory's Intricate Web": A technical revolution provides insight into how the brain links memories, a process critical for understanding and organizing the world around us.
"Black Holes from the Beginning of Time": A hidden population of black holes born less than one second after the big bang could solve the mystery of dark matter.
"How Cities Could Save Us": Urban areas can improve the planet as well as people's lives if we design them to be much more resourceful with energy, water, food and minerals.
"Operation: Diabetes": Surgery that shortens intestines gets rid of the illness, and new evidence shows the gut – not simply insulin – may be responsible.