1. The Great Wall of China is 8,852 km or 5,500 miles long, and it is the only man-made land mark on Earth that can be seen clearly from a satellite up in the space.

2. The Great Wall is about twenty thousand kilometers long.

3. The Great Wall, which is more than 6,000 kilometers long, is the longest wall in the world.

4. It's like a long snake in the north of China.

5. The Great Wall is very famous. It's like a long snake in the north of China.

这些句子都以不同的方式表达了长城的长度，从具体的公里数到形象的比喻，都展现了长城的壮观和悠久的历史。