On that sopping wet Tuesday, many people woke up expecting to find the world palpably different. But it was still Hong Kong, and a decade and a half later, this is still the greatest city ever.
Yet we're not focusing on the Handover; this week, we're all about the number 15. So here, for your delight and delectation, are our top 15 "15-related" facts.
1.The latest superyacht - built from glass and Kevlar, with a range of 4,000 nautical miles, and the capacity to be driven by iPad - is currently docked in Hong Kong where its owners live. It cost GBP15 million.
2. Andy Warhol famously said: "In the future, everyone will be world-famous for 15 minutes". Given the number of reality TV shows, and many people's need to advertise their every move via social media, he might've been on to something.
3. The No 15 bus route on Hong Kong Island goes from Central to The Peak. The No 15 on Kowloon side runs between Hung Hom Ferry and Ping Tin.
4. Woody Allen has received 15 nominations for the best original screenplay Oscar - the most for any writer. (He's won three times.)
5. A 15th anniversary is known as a "crystal" anniversary.
6. There are 15 members in the YP team!
7. Fifteen is the name of Taylor Swift's ninth single, the fourth off her second album Fearless.
8. 15 is a triangular number - the sum of whole numbers starting from 1: 1+2+3+4+5 = 15
9. Justin Bieber was 15 when he released his first EP, My World.
10. In 2002, Jamie Oliver set up a restaurant in London called Fifteen - 15 unemployed, underqualified young people, some from very disadvantaged backgrounds, were chosen as apprentice chefs, in the hopes they'd go into the profession. There are now branches in Cornwall and Amsterdam - the restaurant group continues to train and employ apprentices, and feed profits back into charity.
11. HK$15 - the cost of an MTR ticket from Tung Chung to the Sha Tin Racecourse, or Ma On Shan to Disneyland.
12. Harry Potter and the Philosopher's Stone was released on this day 15 years ago (well, June 30, but it was July 1 in Hong Kong!)
13. When it opened in 1926, the cheapest round trip on the Peak Tram was 15 cents in Third Class.
14. The first score in a game of tennis is 15.
15. There are 15 letters in the words "uncopyrightable", "dermatoglyphics" and "hydropneumatics". These are also among the longest words in the English language that do not repeat a letter.