This is one of the many beautiful postcards I've received from the 'Choose a country' RR on the Postcrossing forum. If I remember correctly, group #500 was a special group, too, and this card is from that group.
Mong Kok is an area in the Yau Tsim Mong District, on the western part of Kowloon Peninsula in Hong Kong. The Prince Edward area occupies the northern part of Mong Kok.
The area is characterized by a mixture of old and new multi-story buildings, with shops and restaurants at street level and commercial or residential units above. Major industries in Mong Kok are retail, restaurants (including fast food) and entertainment. It has been described and portrayed in films as an area in which triads run bars, nightclubs, and massage parlors. With its extremely high population density of 130,000/km2 or 340,000 per square mile, Mong Kok was described as the busiest district in the world by the Guinness World Records.