While we're sure Google Earth works just fine for your daily virtual 'round-the-world travels, the Pro version comes with some really useful features -- even better, it's now completely free. Google Earth Pro, which used to cost an eye-watering $399 per year, gives you the tools to measure 3D buildings and other locations, print high-resolution screenshots, view demographic and traffic layers, and even record your virtual trips. To use it for free, you'll first need to sign up for a license and make sure your PC or Mac meets the minimum system requirements needed to run the program.