The Triangulum Galaxy is a spiral galaxy 2.73 million light-years from Earth in the constellation Triangulum. 

It is catalogued as Messier 33 or NGC 598.  They say it's the third largest galaxy in our part of the sky behind our Milky Way and Andromeda.  

Perhaps it's because it is so far away but I didn't find it to be all that "large" or "bright".  This image is comprised of 247 5 minute exposures (20.58 hours) from my asi071MC OSC camera coupled with the Skywatcher Esprit 120ED (w/Radian Ultra Quadband filter) riding the Skywatcher EQ6r Pro + other bits and pieces.  
Manually processed in PixInsight.

Spiral galaxies are simply beautiful to look at in total.  Among the galaxy's most distinctive features are ionized hydrogen clouds, also called H-II regions, which are massive regions of starbirth.  These show as red highlights in the image and are much like the Hii nebula I photograph in our Milky Way galaxy. Intense ultraviolet radiation from the luminous, massive stars ionizes the surrounding hydrogen gas and ultimately produces the characteristic red glow.  

The bright area in the bottom left of the galaxy structure in this image is known as NGC 604.

Sprawling along loose spiral arms that wind toward the core, M33's giant H-II regions are some of the largest known stellar nurseries, sites of the formation of short-lived but very massive stars.  Among Triangulum's most distinctive features is NGC 604, a region of star-birth so big that the Space Telescope Science Institute once described it as "monstrous." 

Their 2003 estimate says that the gas cloud has more than 200 blue stars and that it is more than 1,300 light years across — or about 100 times bigger than the Orion Nebula. (More recent estimates peg it at 1,500 light-years.)

"If NGC 604 were at the same distance from Earth as the Orion Nebula, it would be the brightest object in the night sky (besides the moon)," NASA stated.

The young stars are extremely hot, at 72,000 degrees F (40,000 C), and the biggest ones are 120 times the mass of the sun. Radiation pumping out from the young stars floods into the gas in the region, making it fluoresce or glow.  Another note of interest to me is the docile nature of the core of this galaxy.