The Layer Walk command in AutoCAD allows you to select one or more layers from a list and immediately isolate them so only the objects on the selected layer or layers are displayed. It can be found in the Layers panel on the Home tab of the ribbon or by typing LAYWALK at the command line. This is a great tool to investigate how a drawing has been put together when you get it from someone else.
You can use the up and down arrow keys to “walk” down the list toggling on and off the objects on each layer. You will quickly answer the question, “what’s on that layer” with the Layer Walk command.