London Wallpapers and Fan Material is an unofficial extension for Chrome. It lets you customize your new tab with bookmarks, apps, games, and London wallpapers. It's fully customizable, and it can be fully removed.

To remove London Wallpapers and Fan Material, just go to your Chrome menu, go to Settings, and find the setting you want to disable (in my case, I found it under Privacy Settings). There, you will find an option named Never Show this again. 

London Wallpapers HD is an unofficial extension made by fans for fans and the copyright belongs to the respective owners of the material and London.