It is hard to go wrong with any photo of a brilliant sunset. But, including a silhouette adds interest to such a photo.
You may note that the pixel dimensions of this picture are larger than the native 6D image size. When you have a solid-colored (or nearly so) border, you only need to keep a sample of that color within the entire side of the frame. In this case, the bottom of the original frame was nearly solid black, but I only left a thin border of that black in the frame.
During post processing, I added size to the canvas and used Photoshop's context-aware fill to paint in that convas addition. The result is a higher resolution image with a comfortable amount of black base.
Image stabilization was relied upon for this 1/6 second exposure.
Camera and Lens Settings
28mm f/8.0 1/6s
5472 x 3816px