What should be hung on the wall behind the sofa in the living room?

This can be done according to your personal preference. You can hang some magnificent paintings, find someone with good calligraphy to inscribe for you, or buy some calligraphers' words to decorate your home. You don't have to hang some words, you can also hang some commemorative decorations such as calligraphy and painting, photo frames, etc. Mainly because you like it yourself.

It is suggested to hang a Feng Shui landscape painting behind the sofa in the living room! There is a saying in Feng Shui: "There are people in charge of the mountains, and the water pipes are rich", which means that people and money are empty and financial resources are rolling. Hanging a landscape painting on the sofa in the living room also implies that there is a backer behind it. A landscape painting of clouds, mountains, water and trees means that financial resources are rolling and people are prosperous. So it is a very wise choice to hang a landscape painting with beautiful mountains and rivers and flowing water behind the sofa in the living room.