If you're curious about the planet you live on, Google Earth is a wondrous thing. Optimized for a tablet, this free app lets you explore remote corners of the globe, including places you may never see in person. Better yet, it may provide some great travel ideas for your next sojourn. Google Earth is a breeze to navigate: Simply move the globe with a finger swipe, and use the ol' two-finger pinch to zoom in and out. The app includes 3-D imagery and flyovers of selected cities, as well as virtual tours of interesting places around the world. Kudos to Google for offering a free app that's fun and educational.