A quick look, maybe it will inspire some history buffs. 
Last weekend marked 100 years since the end of World War I.
The stock markets were treated differently by the war. The outbreak of the war completely surprised the markets, causing the worst financial crisis of the century (the depression of the 30s possibly being the only one worse): uniquely, stock exchanges were closed for half a year (this has never happened on a global scale before or since, at least not yet, WWI). Many people think that WWI was predictable, but for many contemporaries, its realization was a complete surprise, or at least for the financial market (the market is generally very bad at predicting political turns).
In the US and Britain, the stock market performed well even considering inflation, while Germans tasted defeat in the stock market as inflation completely destroyed savings.
Here’s a good paper from Ferguson on markets in the World Wars.
Edit. Blumman’s morning letter also has a good collection of articles:
"The Risk of Another World War
A century after the end of World War I, the chances of such a nightmare happening again seem remote. Of course, they seemed pretty remote 100 years ago, too.
Just before the start of the Great War, Hal Brands writes, Europe hadn’t seen continent-wide hostilities in about a century, and experts thought globalization had ended such great-power conflicts for good. Sound familiar? Then all hell broke loose. The lessons of that, Hal writes, are that peace is more fragile than you realize; that war will be much, much worse than you expect; and that risks rise when the U.S. retreats from the world stage – as it seems to be doing under President Donald Trump. Read the whole thing.
To hammer that last point home, Trump spent the weekend making World War I remembrances in France as awkward as possible, highlighting his ambivalence toward European allies and the post-World War II order the U.S. anchored and enjoyed for decades. So far, this is mostly window-dressing and bluster: His administration has quietly been increasing its spending in Europe, Bloomberg’s editors note. Emmanuel Macron, in response to Trump’s mixed signals, has called for a new European self-defense force. But Europe still can’t muster the kind of manpower and firepower the U.S. provides to NATO, Bloomberg’s editors note.
Still, as Leonid Bershidsky notes, avoiding future conflicts will require a level of cooperation and flexibility not currently in evidence. World War I’s aftermath, Leonid writes, is proof of how poorly handled peace can lead to decades of horror.
More World War I Reading: The war changed the military forever; in many ways today’s armies, navies and air forces are still fighting it. – James Stavridis"