During the 21st century there have been built or are under construction more kilometres of walls than ever in history. Some seek to fight violence, others to stop illegal immigration or the spread of disease; to prevent terrorism, to annex a territory. Some have been built to prevent or hinder civilians –not organized armies, from crossing, or to consecrate the annexation of territories on borders that are not recognized by the international community. Our movie was filmed at four of these walls, but it could have been filmed at any of these: