Article: In September 1828 Chopin, while still a student, visited Berlin with a family friend, zoologist Feliks Jarocki, enjoying operas directed by Gaspare Spontini and attending concerts by Carl Friedrich Zelter, Felix Mendelssohn and other celebrities. On an 1829 return trip to Berlin, he was a guest of Prince Antoni Radziwiłł, governor of the Grand Duchy of Posen—himself an accomplished composer and aspiring cellist. For the prince and his pianist daughter Wanda, he composed his Introduction and Polonaise brillante in C major for cello and piano, Op. 3.

Question: Who directed the operas they enjoyed in Berlin?
Ans: Gaspare Spontini


Article: An important guiding principle of Buddhist practice is the Middle Way (or Middle Path), which is said to have been discovered by Gautama Buddha prior to his enlightenment. The Middle Way has several definitions:

Question: When did Gautama Buddha discover the Middle Way?
Ans: prior to his enlightenment


Article: In most US and Canadian jurisdictions, passenger elevators are required to conform to the American Society of Mechanical Engineers' Standard A17.1, Safety Code for Elevators and Escalators. As of 2006, all states except Kansas, Mississippi, North Dakota, and South Dakota have adopted some version of ASME codes, though not necessarily the most recent. In Canada the document is the CAN/CSA B44 Safety Standard, which was harmonized with the US version in the 2000 edition.[citation needed] In addition, passenger elevators may be required to conform to the requirements of A17.3 for existing elevators where referenced by the local jurisdiction. Passenger elevators are tested using the ASME A17.2 Standard. The frequency of these tests is mandated by the local jurisdiction, which may be a town, city, state or provincial standard.

Question: In what neighboring countries are passenger elevators required to adhere to Standard A17.1?
Ans: most US and Canadian jurisdictions


Article: The chapter house has an original mid-13th-century tiled pavement. A door within the vestibule dates from around 1050 and is believed to be the oldest in England.[citation needed] The exterior includes flying buttresses added in the 14th century and a leaded tent-lantern roof on an iron frame designed by Scott. The Chapter house was originally used in the 13th century by Benedictine monks for daily meetings. It later became a meeting place of the King's Great Council and the Commons, predecessors of Parliament.

Question: A door in the vestible dates back to when?
Ans:
1050