  We live in a universe filled with galaxies with an amazing variety of sizes
and shapes. One of the biggest challenges for astronomers working in this field
is to understand how all these types relate to each other in the background of
an expanding universe. Modern astronomical surveys (like the Sloan Digital Sky
Survey) have revolutionised this field of astronomy, by providing vast numbers
of galaxies to study. The sheer size of the these databases made traditional
visual classification of the types galaxies impossible and in 2007 inspired the
Galaxy Zoo project (www.galaxyzoo.org); starting the largest ever scientific
collaboration by asking members of the public to help classify galaxies by type
and shape. Galaxy Zoo has since shown itself, in a series of now more than 30
scientific papers, to be a fantastic database for the study of galaxy
evolution. In this Invited Discourse I spoke a little about the historical
background of our understanding of what galaxies are, of galaxy classification,
about our modern view of galaxies in the era of large surveys. I finish with
showcasing some of the contributions galaxy classifications from the Galaxy Zoo
project are making to our understanding of galaxy evolution.
  This publication has been made possible by the participation of more than
200,000 volunteers in the Galaxy Zoo project. Their contributions are
individually acknowledged at http://www.galaxyzoo.org/volunteers. KLM
acknowledges funding from the Peter and Patricia Gruber Foundation as the 2008
Peter and Patricia Gruber Foundation IAU Fellow, and from a 2010 Leverhulme
Trust Early Career Fellowship, as well as support from the Royal Astronomical
Society to attend the 28th GA of the IAU.

Cosmology and Nongalactic Astrophysics