Until 1997, Hong Kong was actually a colony of the United Kingdom that was ruled by a governor. Hong Kong is now a Special Administrative Region (SAR). Though it is a part of China, it still has it's own currency, legal system, and parliamentary system for the next 50 years. The Hong Kong dollar is not accepted in the rest of China, and the Chinese Reminibi is not accepted in Hong Kong. That being said, it is currently it's own country.
I couldn't find a picture from the Opening Ceremony, but here's one of Hong Kong walking in the Summer Olympics Opening Ceremony in 2008.
