Flamethrowers became rare in the 19th century, due to improvements in other weapons. Trench warfare made them more useful again, and the German army began using them in 1915. Flamethrowers were used during World War 2 as a bunker clearing device. Many Axis troops used pillboxes and other small fortifications in Northern France, Germany, and on Pacific Ocean islands. Small fire squads used these weapons to draw them out. Although flamethrowers project flames, burning was not the most common form of death associated with these weapons. Rather, smoke released as a byproduct of combustion presented soldiers with the grim ultimatum between death by smoke inhalation or leaving the trench and facing enemy gunfire.