The idea of collisions between galaxies might at first seem unlikely. In general, galaxies are widely scattered, and there exists so much space between one and the next, that only one collision would occur in around 100 times the age of the universe, so that we would not expect to see any of these objects. However, it must be remembered that galaxies often exist in clusters, where the average spacing between cluster members is much smaller.

•   It’s warped. 

                                 The Milky Way is a disk about 120,000 light years across , with a central bulge that has a diameter of 12,000 light years. The disk is far from perfectly flat though, as can be seen in the picture below. What warped it? Two of the galaxy’s neighbors – the Large and Small Magellanic clouds – have been pulling on the dark matter in the Milky Way like in a game of galactic tug-of-war. The tugging sets up a sort of oscillating frequency that pulls on the hydrogen gas (of which the Milky Way has lots of)

•  It has over 200 billion stars

                              As galaxies go, the Milky Way is a middleweight. The largest galaxy known, IC1101, has over 100 trillion stars, and other large galaxies can have more than a trillion stars. Smaller galaxies like the aforementioned Large Magellanic Cloud, have about 10 Billion Stars. The Milky Way has between 200-400 billion stars, but when you look up into the night sky the most you can see from any one point on the Earth is about 2,500. We aren’t stuck with this many stars forever, though, because the Milky Way is constantly losing stars – through supernovae – and producing stars, getting about seven stars per year

                                                        A Galaxy is a massive,  gravitationally bound system consisting of stars, stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component called darkmatter. The word galaxy is derived from the Greek galaxias (γαλαξίας), literally "milky", a reference to the Milky way. Examples of galaxies range from dwafs with as few as ten million (10⁷) stars to giants with a hundred trillion (10¹⁴) stars, each orbiting their galaxy's own center of mass.
                                                      Galaxies contain varying amounts of star systems, star clusters and types of interstellar clouds. In between these objects is a sparse interstellar medium of gas, dust, and cosmic rays. Dark matter appears to account for around 90% of the mass of most galaxies. Observational data suggests that super massive black holes  may exist at the center of many, if not all, galaxies. They are thought to be the primary driver of active galactic nuclei found at the core of some galaxies. The Milky Way galaxy appears to harbor at least one such object.
                                                    Galaxies have been historically categorized according to their apparent shape; usually referred to as their visual morphology. A common form is the elliptical galaxy, which has an ellipse-shaped light profile. Spiral galaxies are disk-shaped with dusty, curving arms. Those with irregular or unusual shapes are known as irregular galaxies and typically originate from disruption by the gravitational pull of neighboring galaxies. Such interactions between nearby galaxies, which may ultimately result in a merging, sometimes induce significantly increased incidents of star formation leading to starbust galaxies. Smaller galaxies lacking a coherent structure are referred to as irregular galaxies