About 10,000 years ago, hunter-gatherers, aided by rudimentary agriculture, moved to semi-permanent villages and never looked back. With further developments came food surpluses, leading to commerce, specialization and, many years later with the Industrial Revolution, the modern city. Vance Kite plots our urban past and how we can expect future cities to adapt to our growing populations.
Biofuels can provide energy without the reliance on environmentally harmful fossils fuels -- but scientists are still searching for a plentiful source. Craig A. Kohn demonstrates how cellulose, the naturally abundant tough walls of plant cells, might be the solution.