So what was Indy's actual job? What did he do that allowed him to travel all throughout the world and have these cool adventures?

I know that he's a college professor that teaches archaeology or whatever, but I took an archaeology gen ed when I was in college and I don't remember my professor being anything like this guy... and I should know because I went to his office hours to talk to him about his job.

So what was it, how is his lifestyle sustainable?