The White House. And, according to a bunch of internet sites, it takes about 570 gallons of white paint to cover the exterior. (Can't help but wonder if the number of gallons would change with the color of paint).
Well, it only took Grayson a few hours to make his 560-piece Lego White House - of course, he didn't have to paint it!
Grayson received this for his birthday, along with some other interesting stuff. Here's the blog link.