It's A Park, Jim
Activision community don Dan Amrich has deployed a less-than-mysterious screenshot for one of the new maps that will feature in Modern Warfare 3's first DLC pack, which is dated for January 24th (if you're an Elite premium subscriber]). The map is apparently called 'Park.' And that's definitely a park. Central Park, maybe?
Remember that the DLC pack will have an outrageously staggered release schedule due to the fact that Activision have split their audience into five different parts.
"Due to a business arrangement from 2010, Xbox 360 gets DLC content ahead of other platforms, and Activision has promised Elite subscribers will get DLC content ahead of the general public. With that in mind, I see five audiences: Xbox 360 Elite, Xbox 360 general public, PS3 Elite, PS3 general public, and PC. I don't yet know in what order each of those audiences will be served. That could get confusing, but you know I'll do my best to make it as easy to figure out as possible."
As I said in the full review, Modern Warfare 3 is big enough to not need DLC. At all. Whether you buy it or not is up to you.