A few months ago I spotted a sign at Nam Cheong Street and Yue Chau Street with a QR Code. If you fancy scanning it, you would be lead to the 'City in Time' site together with a download link at respective App Stores.
The site was down earlier, but it is up and running again now. Some AR stuff that may worth a look. You may also browse the main site as the information is also available there.
ps The app is close to 500 Mb in size, so if there is a mobile data and free space constraint, suggest to use the web version instead.