Why did 20,000 army veterans come pouring into Washington D. C

The reason that 20,000 army veterans came pouring into Washington D. C because they wanted Congress to fund them.

Explanation:

When the World War-I was going on 20,000 veterans and their families marched towards Washington DC. The only purpose was to pressurize congress into choosing for the direct amount of a veteran's bonus assigned for 1945.

The recommendation was to fund veterans $1 for per day toiling in the United States and $1.25 for each day across. Every person with their family in the line in March was well known about the March the were made to do this by their obstacles to life.