Hun Kal (Mercury)

Means "20" in Mayan language.

Hun Kal is a small crater on Mercury that serves as the reference point for the planet's system of longitude. The longitude 's center is defined as being 20° W, thus establishing the planet's prime meridian. (wikipedia entry)

A crater is a circular depression likely created by an impact event. On Mercury they are named after deceased artists, musicians, painters, and authors who have made outstanding or fundamental contributions to their field and have been recognized as art historically significant figures for more than 50 years.