The world will be covered in string this Saturday (9 June) as ambitious knitters cover public structures such as benches, pay stations or trees in crocheted patterns.

The world will be covered in string this Saturday (9 June) as ambitious knitters celebrate the 2nd annual International Yarn Bombing Day.

A type of street art, yarn bombing involves covering a public structure or form (often benches, pay stations or trees) in crocheted or knitted patterns. Since yarn does not damage property in the same way spray paint might, yarn bombers see their art as a way of reclaiming and beautifying public spaces.

International Yarn Bombing Day.was created last year by Alberta knitter Joann Matvichuk as a way to unite the diverse groups of “guerilla knitters” in cities across the world.

“There is a large concentration of yarn bombers on the West Coast, in cities like Vancouver, Seattle, San Francisco and Berkeley,” said Vancouver knitter Leanne Prain, an author who coined the term “yarn bombing” in the book by the same name. “However [the trend] really is all over. I was amazed with how many people joined last year’s event. I heard from people in Europe, Spain and South America.” Last year’s art included handwarmers for a statue in Germany, crochet around a stop sign pole in Michigan, knitted flowers on trees in Nice, France, and hats for street posts in England.

The knitting projects for this year’s celebration are likely well underway, as it can take months to create a covering large enough to surround a big tree or statue. Some taggers knit small cards into their work with a name or website for onlookers to get more information about the artist, but others do the work anonymously, often in the evening or early morning to avoid detection.