See Big Ben towering above the Houses of Parliament, follow St. James Park as it sweeps down to Buckingham Palace.
Sorry I wanted to write a more specific title, but I have a lot to ask in this one sentence.
1) What's 'it' here and how do I know what 'it' is? Is it Big Ben or St. James Park or something else?
2) What's the role of 'as' here? I don't think it means 'because' or 'while' in this sentence.. I just cannot understand what exactly 'as' means here.
3) I also don't understand what 'follow' means here. Does 'follow' here used to mean 'Big Ben is the highest, and St. James Park the second, Buckingham Palce the third'?