Google has unleashed its latest tool to help you find exactly what you're looking for on the World Wide Web - "Sort by subject" in Google Images.

The feature means that if you're looking for something specific, but cannot for the life of you remember what it's called, you can do a more general search and then use Google's subject suggestions to narrow down your results.

For example, if you're looking for a London landmark simply type "London" and then use the subjects to see different categories such as The London Eye, Big Ben, London Bridge and so on. London Bridge obviously showing Tower Bridge in Google's example screenshot. Didn't the Americans make that mistake before?

"Sorting by subject uses algorithms that identify relationships among images found on the web and presents those images in visual groups, expanding on the technology developed for Google Similar Images and Google Image Swirl," explains Donald Tanguay of the Google Images team.

"By looking at multiple sources of similarities, such as pixel values and semantic relationships, and by mining massive amounts of data, we can make meaningful connections and groupings among images."

The new feature is "rolling out globally to nearly every domain and language over the next week", so if you can't get involved yet, you shouldn't have long to wait.