The engineers are the tradesmen of the battlefield. They are responsible for all manner of tasks which facilitate the conduct of operations by the infantry, armour and artillery. Engineers clear paths through enemy obstacles, such as minefields and barbed wire, they bridge rivers and anti-tank tank ditches and build roads, airstrips and landing grounds. Engineers also build obstacles and defensive positions, and lay minefields to resist enemy attacks. The nature of their work often requires engineers to work amongst the most forward of the infantry troops right under the noses of the enemy. An engineer is a fighting soldier in his own right and is known as a "sapper"; they are also nicknamed, in rhyming slang, "ginger beers".