As buildings disappear in earthquake-ravaged Christchurch, it is becoming difficult to remember the city as it was - or even to recognise where you are, in some places.
However, a mobile phone application developed by a group at Canterbury University is ensuring pre-quake Christchurch is always at people's fingertips - and soon what the future may look like.
CityViewAR is a free Augmented Reality (AR) app showing the city as it was before the devastating quakes began in September 2010.
Using an Android mobile phone or iPhone, people can view various sites and see life-sized 3D virtual models of what the demolished buildings looked like, overlaid on a vision of what is there now.
The app also features the option to view sites as they were about a week after the February 2011 quake, and within a couple of months it will allow viewing of models of proposed new designs at demolition sites.