An obliquely angled spiral galaxy dazzles in this NASA Hubble image. But this is no ordinary spiral galaxy - it was cataloged as one of 338 strange galaxies in the Atlas of Strange Galaxies compiled by astronomer Halton Arp in 1966. Many of the galaxies are in the process of interacting with other galaxies, while others are dwarf galaxies without well-defined structures. 
 
What made this galaxy earn its place in the catalog? The single wide, star-speckled spiral arm that appears to be stretching towards us. There are a few patches of gas and stars on the far side of the galaxy, but it doesn't have a similarly impressive spiral arm. 

Image description:

A spiral galaxy seen from a curved angle. The center is a bright spot emitting light. Surrounding this bright center is a thick, stormy disk of material, with strands of dark dust and bright star formation points scattered throughout the disk. A large spiral arm extends from the disk towards the viewer. Some foreground stars can be seen at the top of the galaxy. 

Credits: ESA/Hubble & NASA, J. Dalcanton, R. J. Foley (UC Santa Cruz), C. Kilpatrick