During the September 2010 and February 2011 earthquakes many Christchurch buildings collapsed and many others were subsequently demolished. As a consequence there became many vacant sites in the City and a large number of exposed walls. In time, talented artists painted large art works around the City in an attempt to brighten up what was otherwise a bleak and depressing landscape.
You may have seen the 2010 movie "Exit Through The Gift Shop" about Bansky, a super talented and mysterious graffiti artist who specialises in stencilled street art which suddenly just appears.
In some cases a distinction between street art / graffiti / desecration can be blurred. These images were shot around 2014 and I leave it to you to ponder in which category they fit.
This was in Manchester Street. This is what it now looks like after a re-hash
when some pond-life ruined it with graffiti.