Google Earth 5.0 has been released and includes some new exciting features.
1. Google Ocean
You can now find photos, videos and articles about oceanic and sea life.
Simply enable the “Ocean” layer on the left:

Here is a screenshot showing some info about the Great Barrier Reef:

Here is a screenshot showing some info the Mediterranean Monk Seal:

2. Go back in time
When you become tired of exploring the seas, you can go back in time.
Just click on the top toolbar clock icon:

Here are two New York photos, the first was taken in 1978 and the second in 2009:


And similarly here is the famous London’s Tower Bridge:


3. Plan a space trip to Mars!
Finished flying around the Earth? Well it’s time to explore Mars!
Select Mars from the top toolbar:

Here is a “face” that I have just stumbled upon on Mars:

Google Earth 5.0 – Download
Google Earth 5.0 – Official Announcement


source : http://decoding.wordpress.com/2009/02/03/google-earth-5-dive-into-the-ocean-go-back-in-time-have-a-space-trip-to-mars/