Sometimes, you also need to look at an object or scene from the bottom, from behind, or from the left. The following keys will help you:
Press the Ctrl key and the 7 key on the NumPad. This gives you the Bottom view.
Press the Ctrl key and the 1 key on the NumPad. This gives you Back view.
Press the Ctrl key and the 3 key on the NumPad. This give you the Left view.
Now, press the 1, 3, and 7 keys on the NumPad, then press them while holding down the Ctrl key.
You know how to use the 1, 3, and 7 keys on the NumPad to change views. To see from the opposing angle of a view, you can press the Ctrl key and the number for the view on the NumPad. Pressing the Ctrl + 7 key shows the Bottom view. Pressing the Ctrl + 1 key shows the Back view and Ctrl + 3 shows the Left view.