Is that the place where the border goes right through the center of the library? I’ve been there!
https://en.wikipedia.org/wiki/Haskell_Free_Library_and_Opera_House
The library collection and the opera stage are located in Stanstead, but the main entrance and most opera seats are located in Derby Line. Because of this, the Haskell is sometimes called “the only library in the U.S.A. with no books” and “the only opera house in the U.S.A. with no stage”. Another entrance is accessible directly from Canada, and used to be a backdoor to the stage before, but reconstructed in 2013 in order to remain open to its Canadian visitors without the need to report to customs and immigration of either country.
A thick black line runs beneath the seats of the opera house and diagonally across the center (or centre) of the library’s reading room to mark the international boundary. The stage and half of the seats are in Canada, the remainder of the opera hall is in the US. The building has different postal codes (93 Caswell Avenue, 05830 and 1, rue Church (Church Street), J0B 3E2) and different telephone area codes (+1-802-873-3022 and +1-819-876-2471) in its two respective countries.
The library has a collection of more than 20,000 books in French and English, and is open to the public 38 hours a week.
The building is recognized as a historic site in both countries. In the United States, it has been registered in the National Register of Historic Places since 1976. In Canada, it was designated a National Historic Site of Canada in 1985[3] and has been a provincial heritage site since 1977.
Yup,the Haskell Library...deliberately built on the border to signify international friendship.There's a black line on the floor that is the actual border.Outside the library there's a very small concrete "monument" which represents the border.Also there are flower pots on the street next to it which also represent the border.
Another interesting thing nearby...there's a street called Canusa Street ("Canusa" = Can=>Canada,usa=>USA) which is mainly in Canada but a short part of it (about 1/4 mile) is actually the border.I've driven it...on that portion the cars parked in the driveways on one side have Quebec plates,on the other side they have Vermont plates.