The power of GE5 History
While the media is touting the sea feature, I am far more entranced by the history feature in GE5, and though I would offer some advice on how best to use it. There are a few quirks with it.
Firstly, there is a lot of imagery visible in it that was NOT visible in Google Earth prior. In fact, there's a large chunk that I'm not sure why it's not visible. If you look at the USA, for instance, and click the 'back' button on your history slider just once you'll see all of the States fill in solidly with the exception of Alaska. A few areas are very old imagery, but it's all there.
The 'history' feature is the clock next to the sunlight button. By turning it on, you'll get a slider that allows you to choose which image from which year is being shown. The slider is generally mostly transparent until you put your mouse over it, so don't assume just because it's transparent that there's nothing there.
One other VERY important thing to note is that the level you're zoomed in can affect what GE is going to display for you. If you're zoomed in very close, and there's an image that is a lower resolution image, it won't show up in your slider. Zoom out and it will show up. Be aware that zooming out will also show you more tiles and provide more chances in the general area you can see, so try to find a good point that's focused on the area you want to see, but isn't TOO close up.
Another VERY important point to make is that your placemarks will now remember which image was visible when you last took a snapshot or changed its location. If the user has their history slider active, it will change to that historical image when they click the placemark to view it. I'll include a placemark to demonstrate. I'll post a placemark to the B-2 image for which I provided the overlay a few months back. It's visible in that historical imagery.
One truly awesome thing about this tool is that we probably won't ever lose some images like the scenes of New Orleans right after the hurricane, or Banda Aceh after the tsunami. In addition we can now also flip back and forth and see before, 'during', and after images. This is an amazing thing to me. There's also great power in seeing how some areas have been built up over time in cities.
The historical imagery has also gone back to some amazing 'distances' as well. You can view Las Vegas in 1977, although the image is a little difficult to see. You can see stages of clearing 'Ground Zero' in NYC, and even go back to when the towers were still up. Go take a look at San Francisco in 1946. Yeah, NINETEEN-FOURTY-SIX.
For those looking for imagery in the USA that's not existed thus far, do try what I said and turn on the slider, view the USA, and then click the back button once. You'll probably find some image of the area you want appearing.