At the Spink Shreves Galleries in New York, an auction proved that stamp collectors are still willing to spend money. A stamp collection centered on President Abraham Lincoln brought in almost $2 million (including commissions).

The stamps came from a collection by a retired executive from accounting and consulting firm KPMG. William Ainsworth inherited his father's stamp collection more than 40 years ago. Until 1977, he paid it little mind, but a meeting with a former postmaster general changed his thinking. Ainsworth began to build upon the already substantial collection, with a particular focus on Lincoln.

The collection included 19th and 20th century American stamps with the sixteenth president, along with tax stamps, private issues, proofs and test printings. A mint-condition set of 90 cent stamps (issued in 1869) pulled in $149,600, and a 1909 registered letter with a pair of blue 5 cent Lincoln stamps (sans customary perforations) was good for $77,725.

Postage stamps have featured some of the best art and most beautiful designs over the years, and now your favorites can be yours to enjoy for longer than just the time it takes to send a letter. P.S. Collection by Arjang & Co. is now offering two new timepiece collections that are inspired by some of the most popular U.S. postage stamp designs: the Love series and the holiday series.

The watches range in price from $95-$135 and feature Japanese movement, soft sheepskin and nubuck straps, a space on the back for engraving, and every one is stamped with the official insignia of the United States Postal Service.

Browse the gallery below and tell us which one is your favorite!

Want to know what the most expensive item in the world is by weight and volume? It's not a diamond or other rare gem. It's actually a piece of paper.

Wikipedia pegs it as the so-called Treskilling Yellow stamp from Sweden -- probably the only one of its kind. It has a current value of more than $2 million (or $87 billion per kilogram, according to the site).

Here's what makes it so valuable: Back in Sweden in 1855, when the currency was known as the skilling, the 3 skilling stamp ('treskilling') was printed in green. An 8 skilling stamp was printed in yellow. But due to a printing error, a few 3 skilling stamps were printed in yellow. No one knows how many.

Three years later, Sweden changed its currency and it wasn't until 1886 that a 14-year-old school boy discovered the stamp among his grandmother's possessions and sold it to a dealer for the then-lofty price of 7 kronor. The stamp traded hands several times over the next decade, fetching ever higher prices and inspiring collectors to search for more Treskilling Yellows. But no other was ever found.

By the 1990s the stamp price crossed $1 million for the first time and was setting records every time it changed hands. The last sale was in 1996 when it sold for 2,875,000 Swiss Francs ($2.6 million US) to collectors who remain anonymous. According to the book, The Treskilling Yellow, the stamp is insured for $15 million.