This handy little tool was developed by Mark Russinovich and Bryce Cogswell, and is part of the most execellent SysInternals tool set. It is more than just a simple viewer tool, though.
One of the coolest features of the tool is the ability to take offline snapshots, which you can explore as if it was the live copy of Active Directory. Further, it allows you take multiple snapshots, and compare two snapshots to see what has changed between them.
Other functionality includes that almost of a web browser, with the ability to create bookmarks or favorite places. Advanced searches are available, and you can save those for future use as well.
I highly recommend that you check this out.
SysInternals Active Directory Explorer
URL: https://technet.microsoft.com/en-us/sysinternals/bb963907.aspx
Price: Free