You will be given a definition of a task first, then some input of the task.
This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Passage: Strasbourg's status as a free city was revoked by the French Revolution. Enrages, most notoriously Eulogius Schneider, ruled the city with an increasingly iron hand. During this time, many churches and monasteries were either destroyed or severely damaged. The cathedral lost hundreds of its statues (later replaced by copies in the 19th century) and in April 1794, there was talk of tearing its spire down, on the grounds that it was against the principle of equality. The tower was saved, however, when in May of the same year citizens of Strasbourg crowned it with a giant tin Phrygian cap. This artifact was later kept in the historical collections of the city until it was destroyed by the Germans in 1870 during the Franco-Prussian war.
Output:
In what year did the French Revolution end?