Google has ditched the options in left column design to switch to something similar to how they show results on Tablet PCs.
The options in the left column have been moved to a bar at the top of the search results. It is now available in the US region and would be rolled out internationally in a phased manner.
Google spoke about this update:
If you’re in the U.S., today you’ll notice some changes to the search results page on your desktop. It’s now cleaner and simpler—more consistent with the tablet and mobile design. There’s a greater focus on the answers you’re looking for, whether from web results or from a feature like the Knowledge Graph.
You can access it by using Google.com instead of your localized version of Google.