The following is an excerpt from a travel guide transcript about New York City. I can guess the meaning of high temple in the passage, but I am not sure I know what it means literally and figuratively. I looked it up in a number of dictionaries, but I failed.
New York has always been the gateway to the Land of the Free. But it is also the city of the spree — the shopping spree. The city is shopaholic heaven. And Fifth Avenue with its eye-popping window displays, is the high temple of the retail world.