4K HD Wallpaper: Urban Night
From the streets of Wrocław, Poland is this 4K picture taken by talented photographer Tomasz Bazylinski and available for download under CC0 license from his courtesy. Download if you like optimized for use as desktop background, homescreen phone or to be used in other projects (blogs, apps, templates...) that you might have.
Widescreen Desktop / Macbook (Retina): 2880x1800 (fits on: 2560x1600, 1920x1200, 1440x900)
High Definition HD 1080p: 1920x1080 (fits on: 1600x900, 1366x768, 1280x720)
Samsung Galaxy Tab & iPad: 2048x2048 (compatible with many tablets)
HTC, Samsung Galaxy & iPhone: 1080x1920 (compatible with many phones)