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. -- Lane Turner (41 photos total). Note: You can now follow @bigpicture on the social network App.net, where you own your own data. If you'd like to try it out, we've also got some free invites for our readers.
Workers clean the curtain wall of the 40-story National Bank of Economic Social Development in Rio de Janeiro on December 12, 2012. (Vanderlei Almeida/AFP/Getty Images)