Under the Trump administration, the library has been told by U.S. border officials that it must change the way library patrons coming from the Canadian side enter the facility.

The historical site, where a line taped down the floor marks the border, is celebrated as a symbol of international friendship.

Canadians have enjoyed free access to the library through the stateside front door without having to go through customs. But U.S. Customs and Border Protection says it will begin to restrict Canadians’ access to the border-straddling library.