"What animal does the Great Wall of China look like?"
Because the proper noun does not translate literally between languages. I don't think any Chinese people say 中国的长城. The full name in English is "The Great Wall of China" with "The Great Wall" being a shortened name. The full name in Chinese is 万里长城 with 长城 being a shortened version. 万里长城 literally means "Ten Thousand Li (distance measurement) Long City". 长城 literally means "Long City", (referencing the expectation that cities are surrounded by walls).
More or less. I believe 城 meant "fort" or "fortification" first, and later "town" or "city" by extension, so I think we can say that literally "长城" means "long fortification", but maybe it's a chicken-and-egg scenario.
I'm not against "中国的", though, as, in my experience, Chinese locals explaining things to foreigners can be a little pedantic like that (and I'm sure it goes the other way too), and also when I Google "中国的长城" I get almost 1.5 million results (for whatever that's worth).
Not to mention that we would never say "China's Great Wall of China" to interpret "中国的长城", so "长城" and "Great Wall of China" aren't exactly equivalent.
Sometimes punctuation doesn't seem to be ignored in the Chinese course, so probably because of the period instead of a question mark.
Edit, 2 years later: Most questions in the course have been updated to ignore punctuation (but not spaces) as a matter of policy, so feel free to report any that don't.