“One man’s loss is another man’s gain”
In the year 1939 Berlin was covered in a blanket of darkness, a defensive measure to protect itself. Berlin was having total black outs to protect itself from air raids by the British. The blackout was a measure to ensure that plane could not see any sign of civilization from the sky while flying over the city of Berlin. During the time of the blackouts most of the city was suffering as normal lives were disrupted and crime rates went up. However during this time some people benefitted from the dark and in fact flourished due to the darkness that ensued in the city.
Many saw the blackout as a business opportunity. For a fee, entrepreneurs and small businessmen offered advice on ways meet requirements for the new “blackout” legislation. 
Sale of kerosene lamps, thick card and blackout curtains multiplied, even struggling roll shutters saw a great demand.
Even big businesses such as chemical giant BASF developed an additive called Lumogen, which would lend luminescence to almost any color of pain, dyes, polishes and waxes.
It wasn’t just businesses that saw the blackout as an opportunity, the business of crime was also on a rise. Berlin’s criminals saw this as an opportunity to loot houses and stores as well. There was an increase in incidences of mugging, robbery and crime against property.
The blackout was also a boon for Berlin’s prostitutes. They not only could escape arrest but also use it to their advantages. Even women that were considered “undesirable” earlier could be get work now using the darkness to their advantage.
I guess that adversity might not be for everyone and it is true that one mans loss is another mans gain.