A baktun is a unit of time in the ancient Mayan calendar, specifically part of the Long Count calendar system. One baktun consists of 144,000 days, which is approximately 394.3 years. The Mayans used this system to track longer periods of time, and baktuns are often referenced in relation to significant historical events. The Long Count calendar began in 3114 BCE and is divided into several units, including tun, uinal, and k'in. Each baktun is made up of 20 tuns, and the completion of a baktun is marked by a significant transition in the calendar. The end of the 13th baktun in December 2012 was widely publicized, leading to various interpretations and speculations about its meaning.