4K resolution, also called 4K, refers to a display device or content having horizontal resolution on the order of 4,000 pixels. Several 4K resolutions exist in the fields of digital television and digital cinematography. In the movie projection industry, Digital Cinema Initiatives (DCI) is the dominant 4K standard. In television and consumer media, 4K UHD or UHD-1 is the dominant 4K standard.
By 2015, 4K television market share had increased greatly as prices fell dramatically during 2014 and 2015. By 2025, more than half of US households are anticipated to have a 4K-capable TV (2160p), much faster than the adoption curve of FullHD (1080p).
This video list of collection of some of the famous 4K videos
The World Outside My Window-Time Lapse of Earth from the ISS
GoPro HERO4: The Adventure of Life in 4K
Tomorrowland in 4K
“Eylenda”: Iceland Shot in 4K Ultra HD
Baahubali - The Beginning Release Trailer [4K] | Releasing on July 10th
The Jungle Book Official TRAILER (4K 2160p HD) Disney Live-Action Movie 
4K: X-Men Apocalypse | official trailer US (2016) Bryan Singer Jennifer Lawrence
DEADPOOL Final Red Band Trailer (2016) Marvel Movie [4K ULTRA HD]
4K: Batman v Superman Dawn of Justice | official trailer #3 US (2016) Ben Affleck Gal Gadot