Unbeknownst to many, there are translucent fishing lines that wrap around hundreds of cities around the world. Strung high above the heads of pedestrians and roofs of houses, on utility poles and lamp posts, these wires are barely visible and hardly affect the lives of millions that live in these cities. But for the orthodox Jews, these imperceptible wires that run for dozens of miles, mark an important religious boundary that allow the devoted to hold on to their faith.

The wires mark the boundary of a ritualistic enclosure called an eruv, within which observant Jews can perform certain duties that they are not allowed to outside of home, during Sabbath. These duties are often mundane, like carrying house keys, tissues, medicines, or using strollers to push babies around, but essential enough to function in life. Following the rules of Sabbath, hence, not only interferes with life but also prevents Jews from fulfilling their religious duties. For instance, families with small children, who use prams and pushchairs, or the physically disabled, who use wheelchairs, are effectively housebound. They can't even go to the synagogue.

A section of an eruv in Manhattan, New York. Photo credit: New York Post