The ziggurat you're looking at is John Russell Pope's 1912 design for the Lincoln Memorial. This design and plans for other kooky alternate history monuments are currently on display at the National Building Museum in Washington, DC. Check out parallel universe versions of the Capitol, the White House, and other never-was monuments, like the Washington Dolphin Hotel.

The National Building Museum will have this exhibit on display until May 28, 2012. Here are several of the unused designs, and you can check out an interactive map of the monuments' would-be locations.