Here is a description from ESO on their discovery:

ESO’s VISTA survey telescope has spied a horde of previously hidden massive galaxies that existed when the Universe was in its infancy. By discovering and studying more of these galaxies than ever before, astronomers have for the first time found out exactly when such monster galaxies first appeared.

The newly discovered massive galaxies are marked on this image of the UltraVISTA field.

This is one of the more humorous comments on the video thread regarding the graphics:

That’s how galaxies looked in the early universe they were giant red circles

Commenter DD has made an astute point:

A video that raises more questions than it answers.