may at once be artists and activists, existing in multiple social roles at once. Many border artists defy easy classifications in their artistic practice and work. Images gallery The following pictures show in how many different ways international and regional borders can be closed off, monitored, at least marked as such, or simply unremarkable. See also Border barrier Border control Border irregularities of the United States Borders of the Roman Empire Boundaries between the continents of Earth Boundary delimitation Boundary (real estate) Enclave and exclave France–UK border Geopolitics Illegal entry Illegal immigration Landlocked country Limes (Roman Empire) List of border conflicts List of bordering countries with greatest relative differences in GDP (PPP) per capita List of countries and territories by land borders List of countries by land and maritime borders List of countries that border only one other country List of divided islands List of international river borders List of land borders with dates of establishment List of national border changes from 1815 to 1914 List of national border changes (1914–present) List of territorial disputes Maritime boundary Political geography Political science Quadripoint Schengen Area Tripoint References Further reading The World in 2015: National borders undermined? 11-min video interview with Bernard Guetta, a columnist for Libération newspaper and France Inter radio. "For [Guetta], one of the main lessons from international relations in 2014 is that national borders are becoming increasingly irrelevant. These borders, drawn by the colonial powers, were and still are entirely artificial. Now, people want borders along national, religious or ethnic lines. Bernard Guetta calls this a "comeback of real history"." Baramova, Maria (2010), Border Theories in Early Modern Europe, EGO - European History Online, Mainz: Institute of European History, retrieved: March 25, 2021 (pdf). Said Saddiki, World of Walls: The Structure, Roles and Effectiveness of Separation Barriers. Cambridge, UK: Open Book Publishers, 2017. https://doi.org/10.11647/OBP.0121 Struck, Bernhard, Border Regions, EGO - European History Online, Mainz: Institute of European History, 2013, retrieved: March 8, 2021 (pdf). External links Collection of pictures of European borders, mainly intra-Schengen borders Institut Européen des Itinéraires Culturels homepage Border Ireland – database of activities and publications on cross-border co-operation on the island of Ireland since 1980's Baltic Borderlands Greifswald