Specialists at the Latvian War Museum have restored a unique German and Russian army fort, where one of the most important conflicts of World War I, the Christmas battle, between German invaders and Latvian patriots was fought. The fort,'s name, Tirelpurvs ,derives from swamp and is situated in the swampland where some of the war's heaviest battles unfolded. The wet surroundings meant it was impossible to dig down so the fortification line was built above ground instead. "The peculiarity is that the place itself made it impossible to form the traditional forts in the form of trenches. The swampy surroundings forced soldiers to build the forts above ground," said Dagnis Dedumietis, an expert at the War Museum. At the time of the war Latvia was still incorporated into Tsarist Russia and in the summer of 1915 the troops of Kaiser Germany invaded Latvia and advanced quickly. But 30 kilometres (19 miles) from Riga the invasion came to an abrupt stop. The Russian generals had helped to form the Latvian Rifles divisions through playing on Latvian patriotism. The patriot troops proved a crucial factor in stopping the German invasion reaching Riga. The heaviest Russian military operation on the Riga front during the war, the Christmas battle began on December 23 and lasted for three weeks. The battle was notable because of the Latvian Rifles' new tactic of attacking at night. It was a unexpected night assault that left the enemy with no means of preparing their artillery fire. The assault was divided in two sectors, and the Latvian Rifles succeeded in breaking the front line, settling behind the enemy and consolidating their position. However the attack was stopped at the breached bulwark as reinforcements were never sent. Due to Russian officers' poor command, the Rifles suffered immense casualties, and were forced to return to the captured positions. About 9,000 Rifles fell in the battle. The fort consists of a bulwark, where the inner and outer fences are built of logs. During the war a ditch was dug out in front of the bank, and an extensive line of barbed wire laid out. Behind the bastion there was a bunker for the commander of the military unit. Above it were portholes, covered with sand to absorb bullets. The masked observation post of the fort has been restored, as well as the most solid detail of the entire fort, the machine gun nest. It was built out of concrete and was able to shelter gunners almost completely, as the weaponry were less powerful in those days. "Such machine gun nests were attacked by the Rifles either by brave frontal assaults or left until it was possibile to attack them from the rear, pulling apart the fortification and surrounding the machine gunner. But certainly it involved lots of losses and struggles," Dedumietis said. The rebuilt Tirelpurvs fort takes visitors on a journey emulating the experience the Latvian Rifles might have experienced almost 100 years ago. "It feels more vivid here than reading books or watching movies. Sure, these are not real war circumstances, but one can partly feel the same emotions the soldiers might have felt at that time," visitor Juris Avotins, said. Throughout WWI, the front line divided Latvia in two. Hundred of thousands of people fled the country, almost all factories were evacuated to Russia and Latvia lost one third of its population.