Abandoned footwear

Abandoned footwear, such as a lone boot or shoe, has often been noted in out-of-the-way places like ponds or by the side of roads. Sometimes the shoes may even be new and fashionable.
There are many hypotheses about why this phenomenon seems to more often involve footwear than other types of clothing. Shoes, being more sturdily constructed than most other types of clothing, will last longer after being abandoned outdoors. Leather shoes, for instance, are estimated to last for 25–40 years outside. Some shoe abandonment is intentional, as in shoe tossing, in which shoes are tied together by their laces and thrown in great numbers into trees, over power lines, or over fences.
Artistic use.
Abandoned footwear is a feature in a number of artistic works, including: 
In sport.
Leaving behind shoes can be a symbol of retirement in sport. For example, as ESPN's Sherry Skalko describes about Rulon Gardner's last wrestling bout in Athens, Greece: 
An emotional Rulon Gardner prepares to leave his shoes on the mat -- a symbol of retirement.
After the referee raised Gardner's hand in victory -- first to one side of the arena, then to the other -- Gardner grabbed an American flag, wiped away tears and parked himself in the middle of Mat B like "a 33-year-old kid" and took off his size 13 shoes. First the right one, the one that contains the constant reminder of the snowmobiling accident that almost took his life two years ago, then the left.
Then the super heavyweight bronze medalist stood up, bowed his head at each side of the mat and walked off, leaving his shoes behind, a wrestler's signal that he had fought his final bout.
Seattle Seahawks running back Marshawn Lynch announced his retirement on February 7, 2016 by tweeting a picture of a pair of football cleats abandoned on a telephone wire.
Incidents.
An unusual abundance of abandoned shoes was found on Miami's Palmetto Expressway on Friday, 2 January 2009. Thousands of assorted shoes of all kinds and conditions were scattered across the highway, disrupting traffic for many hours. The shoes were collected for the charity Soles4Souls which redistributes shoes to needy people. This unusually large batch of shoes was expected to go to Haiti.