Question: Immerhof protected blockhouses that were constructed during a war that lasted how long?

Ouvrage Immerhof, also known as Ouvrage Ferme-Immerhof, is one of the largest "petit ouvrages" of the Maginot Line of northeast France.  Located near the community of Hettange-Grande, it is 7 km north of Thionville between the "gros ouvrages" of Molvange and Soetrich, the closest "ouvrage" to the Luxembourg frontier.  It was part of the Fortified Sector of Thionville, in the Fortified Region of Metz, the strongest portion of the Line.  In addition, Immerhof protected other Maginot works in the vicinity: the casemates of Kanfen, the infantry shelter of Stressling, the observation point and shelter of Hettange-Grande, and a number of nearby blockhouses constructed during the Phoney War.  Apart from its function as a communication post between the neighbouring "gros ouvrages", Immerhof also controlled the road and railway routes from Luxembourg, which pass in the immediate vicinity. <SEP> La Reforma (English: The Reform ) or the Liberal Reform was initiated in Mexico following the ousting of centralist president Antonio López de Santa Anna by a group of liberals under the 1854 Plan de Ayutla.  From the liberals' narrow objective to remove a dictator and take power, they expanded their aims to a comprehensive program to remake Mexico governed by liberal principles as embodied by a series of Reform laws and then the Constitution of 1857.  The major goals of this movement were to undermine the power of the Catholic Church in Mexico, separate church and state, reduce the power of the Mexican military, and integrate Mexico's large indigenous population as citizens of Mexico and not a protected class.  Liberals envisioned secular education as a means to create a Mexican citizenry.  The liberals' strategy was to sharply limit the traditional institutional privileges ("fueros") of the Catholic Church and the army.  The law prohibiting the ownership of land by corporations targeted the holdings of the Catholic Church and indigenous communities - confiscating Church land.  Indigenous community lands were held by the community as a whole, not as individual parcels.  Liberals sought to create a class of yeoman farmers that held land individually.  No class of individualistic peasants developed with the Liberal program emerged, but many merchants acquired land (and tenant farmers).  Many existing landowners expanded their holdings at the expense of peasants, and some upwardly mobile ranch owners, often mestizos, acquired land previously held by communities.  Upon the promulgation of the liberal Constitution of 1857, conservatives refused to swear allegiance to it and, instead, formed a conservative government.  The result was a civil war known as the Reform War or Three Years' War, waged between conservatives and liberals for three years, ending with the defeat of the conservatives on the battlefield.  Victorious liberal president Benito Juárez could not implement the envisioned reforms due to a new political threat.  Conservatives had sought another route to regaining power, resulting in their active collaboration with Napoleon III's plans to turn the Mexican Empire into a part into the main American ally of the French empire.  Mexican conservatives offered the crown of Mexico to Hapsburg archduke Maximilian.  The French invasion and republican resistance to the French Intervention in Mexico lasted from 1862-67.  With the defeat of the conservatives and the execution of Maximilian, Juárez again took up his duties as president.  In this period from 1867 to 1876, often called the "Restored Republic" liberals had no credible opposition to their implementation of the laws of the Reform embodied in the 1857 Constitution. <SEP> The Bridestones is a chambered cairn, near Congleton, Cheshire, England, that was constructed in the Neolithic period about 3500–2400 BC.  It was described in 1764 as being 120 yd long and 12 yd wide, containing three separate compartments, of which only one remains today.  The remaining compartment is 6 m long by 2.7 m wide, and consists of vertical stone slabs, divided by a now-broken cross slab.  The cairn originally had a stone circle surrounding it, with four portal stones; two of these portal stones still remain.  The site is protected as a scheduled ancient monument. <SEP> The Phoney War (French: "Drôle de guerre" ; German: "Sitzkrieg" ) was an eight-month period at the start of World War II, during which there were no major military land operations on the Western Front.  It began with the German invasion of Poland on 1 September 1939 and the declaration of war by the United Kingdom and France against Nazi Germany on none }} , and ended with the German attack on France and the Low Countries on 10 May 1940.