Gold price graph with R

Gold is traded in many exchanges all over the world, but the largest ones setting the price of the metal, are three - New York, London and Shanghai. Below is a graph with gold prices from these exchanges during a year. Shanghai(SGE) is trading in physical metal, while New York(Comex) and London(LME) are trading primarily in "paper" gold (ETFs). Daily price difference between Shanghai and New York is displayed on the bottom in red. Also depicted are important events with probable price impact (in blue).

Technical details
The graph is generated by an R application referencing two R libraries - quantmod and rvest. Running time is about one minute.
Data is obtained via web data extraction from the following pages:

Webkit phantomjs is also used to handle some web page Ajax calls.