Wall art: Istanbul
I've been really struck by the graffiti I've seen in Istanbul. In contrast to most graffiti I've seen (e.g. in Argentina or in Brazil) where there's an all-over wallpaper effect, the graffiti artists whose work I've seen so far are remarkably different. They use negative space to great effect, and seem to consider the context of the space where they're working.
In particular, I really like the yellow hands that I see all over the Tünel and Beyoğlu neighborhoods.
Here are some other examples of graffiti in Istanbul.