So what better way to celebrate World Post Day, marked annually on October 9, than thumbing through one of the biggest archives of postcards ever amassed?Swiss entrepreneur Adolf Feller began collecting the cards at the end of the 19th century as souvenirs from trips taken to expand his electrical goods business.Friends and relatives soon pitched in to help supplement his hoard, which passed to his daughter, Elizabeth, on his death in 1931.The collection contains more than 54,000 monochrome and colorful over-painted photographs depicting scenes from 140 countries, including New Zealand, Canada and Uganda.Some of the best postcards have been gathered in a book, "The World in Pocket-Size Format: The Adolf Feller Postcard Collection," by Monika Burri. It's available from Swiss company Scheidegger and Spiess.World Post Day celebrates the creation of the first post union in Feller's home country, Switzerland, in 1874.Postcards appeared about the same time, with picture postcards following soon after.Accidents and natural disastersBack then, postcards weren't just for stirring envy among friends and relations.They were often used to send day-to-day messages rather than just greetings from vacation spots.As well as idyllic scenes, Feller's collection depicts cultural differences and news events, such as accidents and natural disasters.Such postcards were often gathered in albums as mementos in the same way that subsequent generations would collect family vacation snaps.Sadly, the sending of postcards is now a tradition in decline.In 1951, 4.5 billion were delivered in the United States, falling to 1.4 billion in 2010 and fewer than 1 billion today.It's interesting to speculate how Feller would've adapted to the world of online updates.As a businessman whose work involved technology, it's possible he would've been ahead of the curve, tweeting and uploading images from his travels.Then again, such was his enthusiasm for his collection, a post-postcard world might've lacked the same appeal.(CNN)Bakudaily.Az