Most expensive postage stamp
Who
The "Treskilling" Yellow
Where
Switzerland (Geneva)
When

The Swedish "Treskilling" Yellow, a 3 skilling-banco "yellow" stamp was sold for CHF2,870,000 ($2,255,403 / £1,367,969) by David Feldman auctioneers, Geneva, Switzerland on 8 November 1996. Although it was sold again in 2010 for an undisclosed sum, the auctioneer presiding over the sale disclosed that it had fetched at least the 1996 price, and had thus retained its status as the world’s most expensive stamp. The stamp was printed yellow instead of the normal green. Discovered by a schoolboy in 1885 amongst his grandfather's letters when it was sold for seven Swedish crowns, the stamp ended up in the Ferrary collection, being sold for £700. In 1937 King Carol of Romania paid £5,000 and in 1990 it sold for £850,000. It realised SFR 977,500 at an auction by Geneva-based auctioneer David Feldman in March 1984.

When sold in 1996, it became the most expensive thing on this planet by weight.