Hello. See the giant structure in 2D and also in 3D. The positions of the galaxies in the newly found structure are shown in red in the second and third images. Other galaxies in "blue" are located in front or behind "the Giant." 

To relate to the size of things, consider first the Whirlpool Galaxy for example. This bright galaxy is 23 million light years away and 75,000 light years across.  

Credit: NAOJ.

The new find is 65.2 million light years wide and at over 6.7 billion light-year distance. In other words the Giant is about 300 times farther and 900 times larger than the better-known Whirlpool Galaxy. This research was published in Astronomy&Astrophysics: The spectroscopically confirmed huge cosmic structure at z = 0.55, by Masayuki Tanaka et al. 
Based on evidence, the researchers suggest that it is a physically connected structure that extends beyond the probed field. 

“Matter is not distributed uniformly in the Universe,” says ESO's Tanaka. “In our cosmic vicinity, stars form in galaxies and galaxies usually form groups and clusters of galaxies. The most widely accepted cosmological theories predict that matter also clumps on a larger scale in the so-called ‘cosmic web’, in which galaxies, embedded in filaments stretching between voids, create a gigantic wispy structure.”

 Gigantic structure of galaxies 
Credit: ESO.

The Tanaka team made their discovery by combining two of the most powerful ground-based telescopes in the world, ESO’s Very Large Telescope and NAOJ’s Subaru Telescope. They located 17 clumps around the CL0016 cluster at z=0.55.  A clump was classified as a group if there was a strong spatial and redshift concentration of galaxies based on a visual inspection. There is uncertainty, however, over the clumps with weak spatial concentrations as loose groups at this time. 

Over 150 galaxies were studied in detail to obtain a three-dimensional view of the structure. “This is the first time that we have observed such a rich and prominent structure in the distant Universe,” said Tanaka of the Giant. “We can now move from demography to sociology and study how the properties of galaxies depend on their environment, at a time when the Universe was only two thirds of its present age.” 

Credit: ESO. 
Note that in addition to the cluster CL0016 five of the 17 clumps identified in the paper had been published before. Still more is needed beyond the present findings: (1) Wide-field imaging and spectroscopic observations confirm a giant structure around the rich cluster CL0016 at z=0.55; (2) Spectroscopic observations confirmed many of the photometrically identified galaxy groups at the cluster redshift; (3) The structure probed will stay prominent among the structures in the distant Universe with farther extensions to be studied further; (4) The effects of large-scale environments on galaxy evolution have not been revealed yet; (5) Fundamentals are yet to be learnt about the role of structure formation on galaxy properties. 
[1] M. Tanaka - A. Finoguenov - T. Kodama - Y. Koyama - B. Maughan - F. Nakata. The spectroscopically confirmed huge cosmic structure at z = 0.55. Astronomy&Asrophysics, 2009; 505 (2): L9. (Free access.)
[2] Shedding Light on the Cosmic Skeleton - ESO 41/09 - Science Release