Looks like someone didn't clean this one up properly after coming out of the mold.
By NASA / JPL-Caltech / Space Science Institute / Cassini Orbiter - https://medium.com/starts-with-a-bang/the-strangest-moon-in-the-solar-system-bdc675ec411c
https://photojournal.jpl.nasa.gov/catalog/PIA06166 (original mosaic), Public Domain, Link
What's even more intriguing about this ridge that is 20 km wide and 13 km high also matches the equator. It has plenty scientists scratching their heads.
Here it is from the other side, and it is ancient. It even has its own craters.
Image snipped from the "snowy side"
By NASA/JPL/Space Science Institute - PIA08384: The Other Side of Iapetus, Public Domain, Link
