13th Baktun...from that link (along with all the date calculations): "The Maya were a very advanced civilization: outstanding architects "they built the tallest pyramid in the world, La Danta at El Mirador, ['prepare to be amazed'] not surpassed in height until the first skyscraper was erected in 1885...."They were excellent astronomers -their calculations of the solar year have been the most precise of all human history until the invention of very modern instruments of space exploration. They were stunning mathematicians - invented the combined use of the positional numeral system and the zero, centuries before any other civilization." And they predicted 'it will be the end' this 13 Baktun (December 21, 2012). The news already is "the end" is a myth but - presuming our 24 hour/day units are compatible - we don't know yet: the Maya were in Central America so at least 6 hours time difference and we'll have to wait until the end of their day before we really know...so by 6 a.m. on 22/12/12 in the UK well know...if we wake up. Then again, maybe that Maya guy just meant 'it will be the end...of this calendar, make a new one*'!
* They're cyclic anyway so don't end...d'oh.