Copyright law is national in scope, and there is no international copyright law. However, international agreements such as the Berne Convention for the Protection of Literary and Artistic Works provide international protection. Just as the U.S. may not impose formalities requirements for works of foreign origin (so authors of these works may file a lawsuit in U.S. courts even if they have not registered their copyright in the U.S.), other nations that are Berne signatories may not impose such requirement on U.S. authors. That means that U.S. photographers do not need to worry about registering their works in foreign countries or fulfilling similar formalities. However, the ultimate remedy for copyright infringement that takes place in a foreign country is to file a lawsuit in that country’s courts, an undertaking that may be not be worthwhile, depending on the scope of the infringement.