Postage stamps are the most valuable objects on the planet by weight.  

That was made even clearer this year with some spectacular auctions, which showed that the top end of the industry remains hugely attractive to investors.

Read on for our year in review.

Top postage stamp sale of 2016

The Inverted Jenny is a classic American rarity

The Inverted Jenny is the stamp your non-philatelist friends are most likely to have heard of.

The finest known specimen realised $1.1m this year, achieving growth of 7.3% per annum since it was lost sold in 2005

Robert A Siegel, the auction house that handled the sale, explained: "This stamp has always been regarded as one of the finest from the original discovery sheet of 100.

"It is the only inverted jenny to have met the rigorous standards for the xf-superb 95 grade."

2016's most important postage stamp sales

The 1856 cover is rare in that it displays the correct postage from America to France

An 1856 cover sent between New Orleans was one of the year's big highlights, bringing in $62,500. It features four 1856 5c stamps - a strip of three and a single.

The 1847 Mauritius issue is one of the greatest rarities in the hobby, so the sale of the copper plate used to print it was always going to be a big event. In the end it made $1.1m when it crossed the block at David Feldman in December.

1980 Year of the Monkey stamps are massive in China and sheets always attract big bids. A block of 50 realised $192,676 in June.

The 1901 Pan-American series is another popular and highly collectible issue. A fine example of the ultra-rare 2c invert realised $170,000 at Robert A Siegel in October - well above its $55,000 estimate.

The most unusual postage stamp sale of 2016

The cover reads 'Haste, Happy Day! The time we long to see when every son of Adam shall be free!'

This interesting mid-19th century anti-slavery cover was printed in the UK for use in the US. It's one of a number of so-called "propaganda" covers issued during the early years of the postal service.

The lot more than doubled its $7,500 estimate to make $17,000 when it sold at Robert A Siegel in December.

It was a breakout year for…

The 1901 Trinidad one pence is missing its denomination

This 1901 Trinidad one pence error is one of only three singles known to exist, making its sale in at Siegel in November a major event.

It achieved an impressive $37,500.  

It was a year to forget for…

Parisians managed to get post out of their city using hot air balloons

An amazing and exhaustive set of covers from the 1870 siege of Paris, many of which were carried to and from the city via balloon, failed to sell at Spink.

One you may have missed

John Lennon was particularly interested in American stamps

John Lennon and Freddy Mercury's postage stamp collections were on display at Stampex in London in September.

They were both avid collectors when they were boys. Mercury favoured stamps from his native Zanzibar, while Lennon liked those from New Zealand and America.