The ancient and many modern Maya groups believe that the universe has been renewed four previous times. The first attempt at human life produced animals instead; the second produced a people made of clay who would eventually become certain insects (such as ants and bees); the third attempt produced monkeys; and the fourth attempt produced us: "true humans."
Each prior attempt at the human creation was destroyed by a different catastrophe which ended the universe. These stories vary by Maya group: the animals were nearly destroyed by a flood, the people of clay were nearly destroyed by a flood and then a global firestorm, the monkey-people were attacked by their own belongings and their animals.
The astronomically-based Mayan calendar will be completing its first great cycle of approximately 5,200 years on the 21 December 2012. Although there is no substantial evidence that the ancient Maya considered the date significant, many people have postulated that this is the "end of the Universe" from the Mayan perspective, and others believe that the Mayans meant this to symbolize the "coming of a great change."