The expandable spools of razor or barber wire get their name from concertina, a hand-held musical instrument similar to the accordion, with bellows that expand and contract. Concertina wire coils were an improvisation on the barbed wire obstacles used during World War I. They slow down enemies during a war, prevent intruders and prevent prisoners from escaping. - Wikipedia. Today, concertina wire is used once again in the Rio Grande between Ciudad Juárez Mexico and El Paso TX, United States to block the passage of immigrants, refugees and asylum seekers. Photos taken June 2024.