Geograph - photograph every grid square

Graffiti or art?
These mosaic pieces by the French street artist 'Invader' have brightened up the darker places of many cities around the world for several years Link The 'Alien Invasion' of Newcastle took place in 2006 Link The captions to the site photographs clearly indicate that the Newcastle Police did not hold strongly with the art viewpoint, but many pieces are still in place some four years later. Most people now probably fail to see them at all, or think, like I did when first seen, that they were some kind of survey marker or 2D code. The penny dropped for me after seeing a post on the Newcastle Metro Area forum of SkyscraperCity Link
However, there is local evidence for close encounters NZ2464 : The aliens have landed
'Watch this space for invaders' Link
Invader in Wikipedia Link

Pink Lane was part of the system of narrow lanes (the 'pomerium') that used to run along the inside of the Town Walls, and on which no building was allowed. It was named from the Pink Tower, one of the Walls D-shaped, defensive towers, which was located near to the junction of Pink Lane and Clayton Street West.
Tyne and Wear HER(6502): Newcastle, Pink Lane Link