The Mark IV tank was a British tank used during World War I, first introduced in 1917. It was designed to overcome the challenges of trench warfare, featuring a rhomboid shape that allowed it to cross trenches and rough terrain. The tank was equipped with either machine guns or cannons, providing firepower to support infantry. The Mark IV came in two main versions: "Male," which carried machine guns, and "Female," which had only machine guns. With a top speed of about 4 miles per hour, it was slow but heavily armored, making it a significant advancement in military technology at the time.