Here is a quick description of what the site is all about (from Google). I previously created a blog post last year about the site - you can find it here.
Keep exploring with Google Arts & Culture. Meet the people, visit the places and learn about the events that shaped our world. Discover collections curated by experts from the most famous museums. Be moved by stories depicted in thousands of photos, videos, manuscripts and artworks on every type of screen and in virtual reality. Find your favorite artworks, create your own collections and share them with friends.
However, what is going "viral" is that the app matches your face with famous paintings. All you need to do is scroll down on the home page to the 4th "section"
Embedded below is a GIF followed by a 58 second YouTube tutorial.