Question: Where was the German campaign in the country where Luena is located?

full_context: Document 1: Kilamba Kiaxi: Kilamba Kiaxi is one of the six urban districts that make up the municipality of Luanda, in the province of Luanda, Angola's capital.
Document 2: Rangel, Luanda: Rangel is one of the six urban districts that make up the municipality of Luanda, in the province of Luanda, the capital of Angola.
Document 3: Luau, Moxico Province: Luau is a municipality in Angola in the province of Moxico on the border with the Democratic Republic of Congo.
Document 4: Luena, Moxico Province: Luena (pre-1975: Luso) is a town located in east central Angola. It is the administrative capital of Moxico Province. While no exact figures are available, estimates on the population of the city varies from 60,000 to 200,000 residents, including an unknown number of refugees from the Angolan Civil War that officially ended in 2002.
Document 5: History of Angola: Angola is a country in southwestern Africa. The country's name derives from the Kimbundu word for king. It was first settled by San hunter - gatherer societies before the northern domains came under the rule of Bantu states such as Kongo and Ndongo. From the 15th century, Portuguese colonists began trading, and a settlement was established at Luanda during the 16th century. Portugal annexed territories in the region which were ruled as a colony from 1655, and Angola was incorporated as an overseas province of Portugal in 1951. After the Angolan War of Independence which ended with an army mutiny and leftist coup in Lisbon, Angola's independence was achieved on November 11, 1975 through the Alvor Agreement. After independence, Angola later entered a period of civil war that lasted up until 2002.
Document 6: Portugal: In the 20th century, Portugal engaged in two major conflicts: World War I and the Portuguese Colonial War (1961–1974). After the end of the Portuguese Empire in 1975, the Portuguese Armed Forces have participated in peacekeeping missions in East Timor, Bosnia, Kosovo, Afghanistan, Somalia, Iraq (Nasiriyah) and Lebanon. Portugal also conducted several independent unilateral military operations abroad, as were the cases of the interventions of the Portuguese Armed Forces in Angola in 1992 and in Guinea-Bissau in 1998 with the main objectives of protecting and withdrawing of Portuguese and foreign citizens threatened by local civil conflicts.
Document 7: Luanda Municipality: The Municipality of Luanda is one of the seven municipalities that make up the province of Luanda, Angola, as per the new administrative division of the province (the others being Belas, Cazenga, Cacuaco, Viana, Icolo e Bengo and Quiçama). It covers roughly 116 km2 (2nd smallest in province) and includes Ilha do Capo. The population of 2,165,867 in 2014 Census, and projected to be 2,487,444 in 2018 per Instituto Nacional de Estatística, República de Angola.
Document 8: Military history of South Africa during World War II: On 4 September 1939, the United Party caucus refused to accept Hertzog's stance of neutrality in World War II and deposed him in favour of Smuts. Upon becoming Prime Minister, Smuts declared South Africa officially at war with Germany and the Axis. He immediately set about fortifying South Africa against any possible German sea invasion because of South Africa's global strategic importance controlling the long sea route around the Cape of Good Hope.
Document 9: Germans: In 1866, the feud between Austria and Prussia finally came to a head. There were several reasons behind this war. As German nationalism grew strongly inside the German Confederation and neither could decide on how Germany was going to be unified into a nation-state. The Austrians favoured the Greater Germany unification but were not willing to give up any of the non-German-speaking land inside of the Austrian Empire and take second place to Prussia. The Prussians however wanted to unify Germany as Little Germany primarily by the Kingdom of Prussia, whilst excluding Austria. In the final battle of the German war (Battle of Königgrätz) the Prussians successfully defeated the Austrians and succeeded in creating the North German Confederation.
Document 10: British Empire: Britain's fears of war with Germany were realised in 1914 with the outbreak of the First World War. Britain quickly invaded and occupied most of Germany's overseas colonies in Africa. In the Pacific, Australia and New Zealand occupied German New Guinea and Samoa respectively. Plans for a post-war division of the Ottoman Empire, which had joined the war on Germany's side, were secretly drawn up by Britain and France under the 1916 Sykes–Picot Agreement. This agreement was not divulged to the Sharif of Mecca, who the British had been encouraging to launch an Arab revolt against their Ottoman rulers, giving the impression that Britain was supporting the creation of an independent Arab state.
Document 11: German campaign in Angola: Before the official declaration of war between Germany and Portugal (March 1916), German and Portuguese troops clashed several times on the border between German South West Africa and Portuguese Angola. The Germans won most of these clashes and were able to occupy the Humbe region of southern Angola until Portuguese control was restored a few days before the British campaign out of South Africa defeated the Germans.
Document 12: Léua: Léua is a city in Angola of the Moxico province. The municipal headquarters are 62 km east of the provincial capital, Luena.
Document 13: History of Germany during World War I: During World War I, the German Empire was one of the Central Powers that lost the war. It began participation in the conflict after the declaration of war against Serbia by its ally, Austria - Hungary. German forces fought the Allies on both the eastern and western fronts, although German territory itself remained relatively safe from widespread invasion for most of the war, except for a brief period in 1914 when East Prussia was invaded. A tight blockade imposed by the Royal Navy caused severe food shortages in the cities, especially in the winter of 1916 -- 17, known as the Turnip Winter. At the end of the war, Germany's defeat and widespread popular discontent triggered the German Revolution of 1918 -- 19 which overthrew the monarchy and established the Weimar Republic.
Document 14: Cabinda (city): Cabinda (), formerly Vila Amélia, is a city located in the Cabinda Province, an exclave of Angola. Angolan sovereignty over Cabinda is disputed by the secessionist Republic of Cabinda. The municipality of Cabinda covered and contained 598,210 inhabitants in 2014. The residents of the city are known as "Cabindas" or "Fiotes". Cabinda, due to its proximity to rich oil reserves, serves as one of Angola's main oil ports.
Document 15: Northern Seven Years' War: 1762 brought two new countries into the war. Britain declared war against Spain on 4 January 1762; Spain reacted by issuing their own declaration of war against Britain on 18 January. Portugal followed by joining the war on Britain's side. Spain, aided by the French, launched an invasion of Portugal and succeeded in capturing Almeida. The arrival of British reinforcements stalled a further Spanish advance, and the Battle of Valencia de Alcántara saw British-Portuguese forces overrun a major Spanish supply base. The invaders were stopped on the heights in front of Abrantes (called the pass to Lisbon) where the Anglo-Portuguese were entrenched. Eventually the Anglo-Portuguese army, aided by guerrillas and practicing a scorched earth strategy, chased the greatly reduced Franco-Spanish army back to Spain, recovering almost all the lost towns, among them the Spanish headquarters in Castelo Branco full of wounded and sick that had been left behind.
ground_truth: Portuguese Angola
sub_queries: Luena >> country Answer: Angola
German campaign in Angola >> location Answer: Portuguese Angola