instruction:
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.
question:
By 1860, Houston had emerged as a commercial and railroad hub for the export of cotton. Railroad spurs from the Texas inland converged in Houston, where they met rail lines to the ports of Galveston and Beaumont. During the American Civil War, Houston served as a headquarters for General John Bankhead Magruder, who used the city as an organization point for the Battle of Galveston. After the Civil War, Houston businessmen initiated efforts to widen the city's extensive system of bayous so the city could accept more commerce between downtown and the nearby port of Galveston. By 1890, Houston was the railroad center of Texas.
answer:
What commodity was Houston known for in 1860? 


question:
At Maecenas' insistence (according to the tradition) Virgil spent the ensuing years (perhaps 37–29 BC) on the long didactic hexameter poem called the Georgics (from Greek, "On Working the Earth") which he dedicated to Maecenas. The ostensible theme of the Georgics is instruction in the methods of running a farm. In handling this theme, Virgil follows in the didactic ("how to") tradition of the Greek poet Hesiod's Works and Days and several works of the later Hellenistic poets. The four books of the Georgics focus respectively on raising crops and trees (1 and 2), livestock and horses (3), and beekeeping and the qualities of bees (4). Well-known passages include the beloved Laus Italiae of Book 2, the prologue description of the temple in Book 3, and the description of the plague at the end of Book 3. Book 4 concludes with a long mythological narrative, in the form of an epyllion which describes vividly the discovery of beekeeping by Aristaeus and the story of Orpheus' journey to the underworld. Ancient scholars, such as Servius, conjectured that the Aristaeus episode replaced, at the emperor's request, a long section in praise of Virgil's friend, the poet Gallus, who was disgraced by Augustus, and who committed suicide in 26 BC.
answer:
Which long didactic hexameter poem did Virgil work on for several years?


question:
Warsaw's first stock exchange was established in 1817 and continued trading until World War II. It was re-established in April 1991, following the end of the post-war communist control of the country and the reintroduction of a free-market economy. Today, the Warsaw Stock Exchange (WSE) is, according to many indicators, the largest market in the region, with 374 companies listed and total capitalization of 162 584 mln EUR as of 31 August 2009. From 1991 until 2000, the stock exchange was, ironically, located in the building previously used as the headquarters of the Polish United Workers' Party (PZPR).
answer:
When was Warsaw's first stock exchange established?