Problem: In 1852, Elisha Otis introduced the safety elevator, which prevented the fall of the cab if the cable broke. The design of the Otis safety elevator is somewhat similar to one type still used today. A governor device engages knurled roller(s), locking the elevator to its guides should the elevator descend at excessive speed. He demonstrated it at the New York exposition in the Crystal Palace in a dramatic, death-defying presentation in 1854, and the first such passenger elevator was installed at 488 Broadway in New York City on March 23, 1857.
What feature did the safety elevator display?
The answer is the following: prevented the fall of the cab if the cable broke

Problem: While the French army under General MacMahon engaged the German 3rd Army at the Battle of Worth, the German 1st Army under Steinmetz finished their advance west from Saarbrucken. A patrol from the German 2nd Army under Prince Friedrich Karl of Prussia spotted decoy fires close and Frossard's army farther off on a distant plateau south of the town of Spicheren, and took this as a sign of Frossard's retreat. Ignoring Moltke's plan again, both German armies attacked Frossard's French 2nd Corps, fortified between Spicheren and Forbach.
Who commanded the German 1st Army?
The answer is the following: Steinmetz

Problem: Brasilia has also been the focus of modern-day literature. Published in 2008, The World In Grey: Dom Bosco's Prophecy, by author Ryan J. Lucero, tells an apocalypticle story based on the famous prophecy from the late 19th century by the Italian saint Don Bosco. According to Don Bosco's prophecy: "Between parallels 15 and 20, around a lake which shall be formed; A great civilization will thrive, and that will be the Promised Land." Brasilia lies between the parallels 15 S and 20 S, where an artificial lake (Paranoa Lake) was formed. Don Bosco is Brasilia's patron saint.
What lake did Don Bosco predict?
The answer is the following: Paranoa Lake

Problem: The build was released for download later in the day in standard 32-bit and 64-bit versions, plus a special 64-bit version which included SDKs and developer tools (Visual Studio Express and Expression Blend) for developing Metro-style apps. The Windows Store was announced during the presentation, but was not available in this build. According to Microsoft, there were about 535,000 downloads of the developer preview within the first 12 hours of its release. Originally set to expire on March 11, 2012, in February 2012 the Developer Preview's expiry date was changed to January 15, 2013.
When did the developer preview expire?
The answer is the following:
January 15, 2013