The man, who’s wife knows how to play the violin, plays the piano.
Answer:
The Great Wall of China is one of the most famous landmarks in the world. The Great Wall is made up of many different walls and fortifications built over the course of more than two thousand years. The Great Wall is over 13,000 miles long.
Explanation:
All the other sentences seem a little off-topic. But the second sentence does it perfectly.
I should be a comma after "not" I believe.
