Step 1: Identifying the site.
The Terracotta Army in China is the famous historical site known for its collection of terracotta statues. Machu Picchu, Stonehenge, and Black Sun do not feature terracotta statues.
Step 2: Analyzing the options.
- (1) Machu Picchu: Incorrect, it is not known for terracotta statues.
- (2) Stonehenge: Incorrect, it is a prehistoric monument made of stone.
- (3) Black Sun: Incorrect, this is not a terracotta-related site.
- (4) Terracotta Army: Correct, this is the famous site known for its vast collection of terracotta statues.
Step 3: Conclusion.
The correct answer is Terracotta Army, which is option (4).