If you ask them, homeless veterans might tell you they only have a vague idea of what they look like, or how they got to where they are. At least that was true of the few we met in San Diego.

There are about 50,000 homeless vets in the U.S., according to the Department of Veterans Affairs. Veterans who have struggled with drug use or mental illness, unemployment or criminal records — or any number of things. The VA says it plans to end homelessness among vets by 2015.

Homeless veterans, though, may not see themselves as “homeless veterans” at all. If you passed one on the street, you might not even know it.