Google Maps owns me

My Mother-in-Law said it best when we were talking about google maps, I am an arm chair traveller now... but another what the hell is that, this time in London. This one looks like lots of little craters. Curious. At first I though it may have been where they are doing some construction, but it is like 100city blocks in size, and even some of the city blocks around it are pockmarked, very interesting indeed.
No one answered me on the thing in Mexico, and I couldn't find anything in google on it, the only half plausible answer I got is Mexico is building Killer Klowns of Mass Destruction, from Zlatko...
Anyone?
Peace out all.