Among the updates to Google Earth are the following:

New and updated imagery from Mars

UNESCO World Her­itage Sites

3D build­ing facades for 5 cities in CA, and now Philadel­phia, Port­land, Austin &  Chicago

From the UN Cli­mate Change Con­fer­ence (COP15) is Cli­mate Change Tours

Source: The Sight­seer Newslet­ter | Decem­ber 2009

Google Earth Sight­seer Newslet­ter [googlearth@google.com]