As a symbol of the German annexation, Chancellor Adolf Hitler celebrated Christmas 1940 at the former bergamt of the Imperial District of Metz, but local people largely rejected the German occupation. Multiple French Resistance cells were active during this period in the region of Metz, such as the Mario and the Derhan groups, whose activities included collecting arms for the Liberation, distributing flyers, helping prisoners and resisters, and sabotage. Several "resistants" were detained and tortured in the Fort of Queuleu in Metz and Jean Moulin died in Metz's railway station while on a train in transit to Germany. In 1944, the attack on the city by the U.S. Third Army under the command of General George S. Patton faced heavy resistance from the defending German forces. The Battle of Metz lasted for several weeks and Metz was finally captured by the Americans in November 1944, and the city reverted to France after the war. During the 1950s, Metz was chosen to be the capital of the newly created Lorraine region. With the creation of the European Communities and the latter European Union and under the leadership of Robert Schuman, Metz became a central place of the Greater Region and the SaarLorLux Euroregion. In 1979, the city was home to the Metz Congress, the seventh national congress of the French Socialist Party, during which future French President François Mitterrand won the nominating process of the French presidential election of 1981 after defeating the internal opposition led by Michel Rocard. Later, Pope John Paul II delivered a Mass in the Saint-Stephen Cathedral during his visit to Metz in 1988 and pleaded in his speech for the European unity in the context of the Cold War. In 2010, Metz opened a branch of the French National Museum of Modern Art, the Centre Pompidou-Metz, designed by Japanese architect Shigeru Ban and inaugurated by French President Nicolas Sarkozy.