Photos: Longest-reigning popes

With the resignation of Pope Benedict, take a look at history's longest-reigning popes, or <a href='http://www.cnn.com/2013/02/12/world/gallery/shortest-reigning-popes/index.html'>check out history's shortest-reigning popes</a>.<!-- -->
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</br>No. 10 (10th longest-reigning pope): Pope Urban VIII reigned for 20 years, 11 months and 24 days from 1623 to 1644.

With the resignation of Pope Benedict, take a look at history's longest-reigning popes, or check out history's shortest-reigning popes.

No. 10 (10th longest-reigning pope): Pope Urban VIII reigned for 20 years, 11 months and 24 days from 1623 to 1644.