The View From The Top
If you don't mind the 311 steps, one of the best view of the city is from the top of the Monument. Wren designed it, although it went through several revisions:
Wren at first proposed a pillar with sculptured flames of gilt bronze issuing from loopholes in the shaft, and a phoenix on the summit rising from her ashes, also of gilt bronze. This, on further consideration, he found unsuitable, and then designed a statue of Charles II, 15 feet high. The statue was, however, found to be impracticable on the ground of expense, and the present vase or urn of flames was therefore substituted.