When users launch the Google ( GOOG) Earth app, up pops a globe that can be spun and manipulated via pinching. Users double-tap the sphere to zoom in on any country, city or block in the world; a swipe with two fingers allows the viewing of mountainous terrain. Selecting one of the categories on the "layers" feature pulls up names of significant places, businesses and Wikipedia entries related to landmarks you're viewing on the map. If you're having trouble finding a precise location, you can look for it via the search bar. And no matter how far you've traveled around the world on the app, tapping its "location" button automatically "flies" you back to the exact block where you -- and your iPad -- are located.