How do they do this?

I'm wondering how they get the foreground image of the city in here and how they get it to stay in place over the page.

http://www.youlove.us

They've probably got it on a layer in the flash file above another layer that has a big fat background for everything, and when you click something, that background moves up or down to whatever location you're going to.
The way they did it runs kind of slow, though...

(edit)
I'm wasted. That's all javascript.
They do it by placing a div with the city picture on a high z level at an absolute position, and then calling a bunch of setInterval calls that change the absolute position of a big fat div in the background, that... (copy paste)

PHP Code:

---

#footer{
    position:fixed;
    bottom:0; 
    left:0;
    width:100%; 
    height:40%; 
    background:url(/graphics/bg-footer.png) repeat-x 50% 0;
    z-index:30;
    } 


---

This is the code for the city picture.

Thanks for the info, dudes!