I'm staying at the Radisson next the runways at SMX, and saw a DC-10 sitting on the apron. I was curious so walked over to get a look. It has a huge belly tank, turns out to be a fire retardant delivery plane for wildfires, 11,600 gallons at a time.
Here's the company website.
http://www.10tanker.com/the-plane.html
Kinda cool, something I hadn't seen before. I didn't realize they used planes this big.
(Madone59 suggested I post it in this thread, too.)