A painter’s dogged, doomed pursuit of the perfect $100 bill.

The impact, both on researchers and patients, of a radical treatment.

On riding China’s Qinghai-Tibet Railway just before it opened:

Staring out at the shimmering tracks and concrete-reinforced embankment extending to the horizon, I can’t help but think of the senior Chinese scientist who confessed to me that the rail line he helped build might not be safe for long.