They keep things out or enclose them within. They're symbols of power, and a means of control. They're canvases for art, backdrops for street theater, and placards for political messages. They're just waiting for when nobody's looking to receive graffiti. Walls of all kinds demarcate our lives.
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Workers clean the curtain wall of the 40-story National Bank of Economic Social Development in Rio de Janeiro on December 12, 2012.