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Trench warfare
Trench warfare is a type of land warfare using occupied lines largely comprising military trenches, in which troops are well-protected from the enemy's small arms fire and are substantially sheltered from artillery. Trench warfare became archetypically associated with World War I , when the Race to the Sea rapidly expanded trench use on the Western Front starting in September 1914.
Trench warfare proliferated when a revolution in firepower was not matched by similar advances in mobility, resulting in a gruelling form of warfare in which the defender held the advantage. On the Western Front in 1914–1918, both sides constructed elaborate trench, underground, and dugout systems opposing each other along a front, protected from assault by barbed wire. The area between opposing trench lines was fully exposed to artillery fire from both sides. Attacks, even if successful, often sustained severe casualties.The development of armoured warfare and combined arms tactics permitted static lines to be bypassed and defeated, leading to the decline of trench warfare after the war. Following World War I, "trench warfare" became a byword for stalemate, attrition, sieges, and futility in conflict.
A Zeppelin is a type of rigid airship named after the German inventor Count Ferdinand von Zeppelin After the outstanding success of the Zeppelin design, the word zeppelin came to be commonly used to refer to all rigid airships. Zeppelins were first flown commercially in 1910 by Deutsche Luftschiffahrts-AG , the world's first airline in revenue service. By mid-1914, DELAG had carried over 10,000 fare-paying passengers on over 1,500 flights. During World War I, the German military made extensive use of Zeppelins as bombers and as scouts, resulting in over 500 deaths in bombing raids in Britain.
In 1917, following losses to the air defences over Britain, new designs were produced which were capable of flying at much higher altitudes, typically operating at around 6,100 m . This was achieved by reducing the weight of the airship by reducing the weight of the structure, halving the bomb load, removing the defensive armament and by reducing the number of engines to five.However these were not successful as bombers: the greater height at which they operated greatly hindered navigation, and their reduced power made them vulnerable to unfavorable weather conditions.