The world's most expensive postage stamp, a one-of-a-kind issue printed in Sweden in 1857, has been sold at an auction in Geneva.
The Treskilling Yellow, or three shilling stamp, was issued by mistake during a print run of eight skilling stamps, which are yellow.
The three skilling was normally green.
Neither the identity of the buyers nor the price was disclosed.
The last time it was sold, in 1996, it fetched 2.88 million Swiss francs ($US3 million) at auction.
