This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.

Paris is the home of the most visited art museum in the world, the Louvre, as well as the Musee d'Orsay, noted for its collection of French Impressionist art, and the Musee National d'Art Moderne, a museum of modern and contemporary art. The notable architectural landmarks of Paris include Notre Dame Cathedral (12th century); the Sainte-Chapelle (13th century); the Eiffel Tower (1889); and the Basilica of Sacre-Cur on Montmartre (1914). In 2014 Paris received 22.4 million visitors, making it one of the world's top tourist destinations. Paris is also known for its fashion, particularly the twice-yearly Paris Fashion Week, and for its haute cuisine, and three-star restaurants. Most of France's major universities and grandes ecoles are located in Paris, as are France's major newspapers, including Le Monde, Le Figaro, and Liberation.
What is the most visited art museum in the world?

Most light bulbs have either clear or coated glass. The coated glass bulbs have a white powdery substance on the inside called kaolin. Kaolin, or kaolinite, is a white, chalky clay in a very fine powder form, that is blown in and electrostatically deposited on the interior of the bulb. It diffuses the light emitted from the filament, producing a more gentle and evenly distributed light. Manufacturers may add pigments to the kaolin to adjust the characteristics of the final light emitted from the bulb. Kaolin diffused bulbs are used extensively in interior lighting because of their comparatively gentle light. Other kinds of colored bulbs are also made, including the various colors used for "party bulbs", Christmas tree lights and other decorative lighting. These are created by coloring the glass with a dopant; which is often a metal like cobalt (blue) or chromium (green). Neodymium-containing glass is sometimes used to provide a more natural-appearing light.
What is the powdery substance in coated glass light bulbs?

During the early High Middle Ages, Germany was ruled by the Ottonian dynasty, which struggled to control the powerful dukes ruling over territorial duchies tracing back to the Migration period. In 1024, they were replaced by the Salian dynasty, who famously clashed with the papacy under Emperor Henry IV (r. 10841105) over church appointments as part of the Investiture Controversy. His successors continued to struggle against the papacy as well as the German nobility. A period of instability followed the death of Emperor Henry V (r. 111125), who died without heirs, until Frederick I Barbarossa (r. 115590) took the imperial throne. Although he ruled effectively, the basic problems remained, and his successors continued to struggle into the 13th century. Barbarossa's grandson Frederick II (r. 12201250), who was also heir to the throne of Sicily through his mother, clashed repeatedly with the papacy. His court was famous for its scholars and he was often accused of heresy. He and his successors faced many difficulties, including the invasion of the Mongols into Europe in the mid-13th century. Mongols first shattered the Kievan Rus' principalities and then invaded Eastern Europe in 1241, 1259, and 1287.
What dynasty controlled Germany in the early High Middle Ages?