World War I began July 28, 1914—100 years ago this week. The articles (and occasionally grasping historical parallels) have been coming fast and furious ever since. I especially recommend three. The Washington Post features an incredible gallery of WWI landscapes, then and now. Graham Allison in The Atlantic offers a clear-headed assessment of the similarities—and differences—between the conditions of 1914 and 2014. Finally, Stephen Walt in Foreign Policy breaks down the most significant lesson of WWI. He argues that historians focus too much on why the war began…and not enough why it lasted so long.