The 3-D Maps for Seven Worlds are coded using a markup language called VRML (Virtual Reality Modeling Language). There are dozens of programs, apps and plug-ins on the web that read these files, for all major desktop and laptop platforms. What follows are some of the ones we've tried or seen.
NOTE: The list below is updated as of December 2016. We haven't tested ALL of these alternatives, and are certainly not recommending/endorsing any of them. Also, note that there are many more VRML viewers than we have space to list here. If you don't find a viewer you like here, keep looking!
Your best bet is Cortona 3D Viewer, and it's the one I use the most. It's a fully-fledged plugin for Internet Explorer (also runs on Windows 10). Note that you need to disable Protected Mode in Internet Explorer for Cortona to work correctly.
Another great option is InstantReality InstantPlayer. InstantPlayer is a very flexible VRML player. Besides supporting many types of views, it also has versions for OSX and Linux.
Besides those two, other available options are Coin VRML Viewer (a good small, portable viewer, although not as flexible as the others) and View3DScene (a basic but flexible VRML Viewer). Although FreeWRL technically works, it is the most complex and least-user friendly of the bunch.
Your two best bets with Apple OSX are InstantReality InstantPlayer and View3DScene. InstantPlayer is somewhat better looking but View3DScene is functional and effective. Note that depending on the version of OSX you have you may have to install previous versions of InstantPlayer.
iOS and Android
Most VRML plugins and applications are available for desktop and laptop Operating Systems, making it difficult to see VRML on phones and non-Windows tablets. What follows is a list of some VRML plug-ins that exist in the Apple Store and Google Play store, but which so far have yielded unsatisfactory results. Your mileage may vary, but I suggest you focus on desktop viewers first.