Short answers, pulled from the story.
Silesia lies mostly within Poland, with smaller parts in the Czech Republic and Germany. Within Poland it is divided between Lubusz Voivodeship, Lower Silesian Voivodeship, Opole Voivodeship, and Silesian Voivodeship. The German portion is part of the federal state of Saxony.
From June 1945 to January 1947, 1.77 million Germans were expelled from Lower Silesia and 310,000 from Upper Silesia. Nearly all of the 4.5 million Silesians of German descent fled or were expelled. The population of Głogów fell from 33,500 to 5,000, and Wrocław's population dropped by 25% between 1939 and 1966.
King Frederick II of Prussia seized most of Silesia from Austria in 1742 during the War of the Austrian Succession. The region formally became the Prussian Province of Silesia in 1815 and entered the German Empire when it was proclaimed in 1871.
The League of Nations plebiscite of 1921 produced 60% of votes for Germany and 40% for Poland. Despite the majority voting for Germany, following the third Silesian uprising in 1921 the Entente Powers awarded the easternmost portion of Upper Silesia, including Katowice, to Poland.
The Silesian language is spoken by a minority in Upper Silesia and reflects the region's mixed Polish and German heritage. There is ongoing debate about whether it should be considered a dialect of Polish or a separate language; the question remains unresolved.
Silesia is one of the world's major coal-producing regions, with 41 mines mostly in the Upper Silesian Coal Basin. Annual production includes roughly 95 million tonnes of bituminous coal, 571,000 tonnes of copper, and 160,000 tonnes of zinc. In 2008, an estimated 35 billion tonnes of lignite reserves were found near Legnica, among the largest deposits in the world.