once famously featured in an episode of the Simpsons A rare US postage stamp has sold for $2m (£1.63m) in a New York auction, setting the record for the most expensive single US stamp sold.

The British Penny Black is coveted among stamp collectors, and while your run-of-the-mill Penny Black could be had for less than $15, the most sought-after are much more expensive. In June 2011 ...