Tragedies necessitating inventions

I am currently working on a paper that focuses on inventions being created in the midst of tragedy. For example, as President James Garfield lay dying of an assassin's bullet, Alexander Graham Bell hurriedly invented a crude metal detector in an unsuccessful attempt to locate the fatal slug. Garfield's assassination also gave birth to a rudimentary air conditioner. As he was dying, naval engineers constructed a box-like structure containing cloths saturated with melted ice water, where a fan blew hot air overhead. This contraption was able to lower a room by 20 degrees Fahrenheit but consumed half a million pounds of ice in two months' time.

The canning process is another example, as it is a product of the Napoleonic wars. Malnutrition was rampant among the 18th century French armed forces. As Napoleon prepared for his Russian campaign, he searched for a new and better means of preserving food for his troops and offered a prize of 12,000 francs to anyone who could find one. Nicolas Appert, a Parisian candy maker, was awarded the prize in 1809.

It is said that necessity is the mother of invention. I am specifically looking for past necessities that arose during tumultuous times and have yielded inventions bettering humanity. Any input would be greatly appreciated!