World War I

World War I, called the "Great War" by the British, lasted from 1914-1918 and was one of the most terrible conflicts in history. The horrors of trench warfare and poison gas contributed to the destruction of the greater part of an entire generation of young men in Europe.  Here are some of the photos to come out of that war.

 American soldiers advancing on a bunker

 Army wagons

 Australian infantry wearing gas masks, Garter Point

 Austrian troops executing Serbs

 Baron Manfred von Richtofen and Jasta 11

Baron von Richtofen (famously known as the "Red Baron") 

was Germany's top flying ace during World War I with 80 confirmed kills.

The Jasta 11 was Richtofen's flying squadron.

Bavarian Landsturm mortar crew with 15cm Magener Werfer

 British 55th Division troops blinded by gas

 British artillery battery at Mount Scopus

 

 British infantry advancing through gas at Loos
  

 British officers interrogating Turkish prisoners at Cape Helles

 

 British trench near Ovillers-la-Boisselle

 

 British wounded during Battle of the Somme

The Battle of the Somme was the deadliest single battle of the war.  Lasting for months and inflicting horrific casualties on both sides, the battle came to be a symbol of the futility of trench warfare, as essentially no ground was gained. It also was seen (eventually) as an example (one of many) of the incompetence of the British General Staff which planned the offensive. More than a million total casualties resulted from this battle.
There's some video footage from the Somme on YouTube.
Also a full-length documentary (over an hour long).

British tanks

World War 1 was the first conflict in which tanks were used.

 

American soldiers returning home on the Agamemnon, Hoboken, New Jersey, 1918