Atlas Obscura:

For nearly 200 years Derby Line, Vermont, and Stanstead, Quebec, essentially functioned as one town. Citizens drank the same water, worked in the same tool factory, played the same sports (primarily curling), fought in the same world wars, and were born in the same hospital in nearby Newport, Vermont. They also shared the same cultural center, the Haskell Free Library and Opera House, an ornate Victorian edifice built deliberately on top of the international border in 1901 by the Canadian wife of a wealthy American merchant.

Today, it is the only library in the world that exists and operates in two countries at once.

One of many fascinating stories about life along the Canada-US border. I live only a few miles from it and often see the border obelisks along the road, reminding me that our two countries are close in many ways.