Said R. Joshua ben Levi: "On what account do they prepare an eruv of courtyards? It is for the sake of peace." There was the case of a woman who was on bad terms with her neighbor. She sent her contribution to the eruv with her son. The neighbor took him and hugged and kissed him. He went and told his mother this. She said, "Is this how she loved me, and I did not know about it!" They thus became friends once again.
Jerusalem Talmud, Eruvin 3:2, 20d
In response to the booming Jewish community in Midtown and Greenwhich Village, rabbinic and lay leaders of all denominations joined together to extend the Manhattan Eruv, which then included the Upper East Side and West Side, south to Houston Street.
In response to the growing downtown Jewish communities the eruv has expanded again. To read more about the expansion and how to support it click here.