First met with HR. They asked very generic questions about your core beliefs and things that are important to you. They wanted to make sure I was a good fit for the culture - working in teams and having leadership roles I believe is what helped me get in.
Then they flew me to the corporate office which involved three different interview for three different global practices (yes, you could potentially have three or four different job offers from a single company.)
To start the "interviews" I had to give a brief presentation on my background. I talked about why I wanted to become an engineer, the roles I have played on teams, my background on internships, and why I really wanted to work for Burns and McDonnell.
After the presentation I met with three different division managers one on one. Each division manager talked about what their global practice/division does for about 30 minutes. They then asked me about four or five questions and opened the remaining 20 minutes to questions I had for them.