"Proving the Perfection of the Honeycomb", by Dana Mackenzie. Science, 27 August 1999, pages 1338-1339.
The hexagonal cells of honeycombs allow bees to store honey efficiently: The shape of the cells maximizes the amount of honey stored per cell and minimizes the amount of wax needed to create the cells. Although scientists long believed that the honeycomb shape was the most efficient possible, it was only this past summer that this belief was nailed down as a mathematical fact. The result was proven by Thomas Hales, who last year proved the celebrated Kepler Conjecture.
--- Allyn Jackson