Precambrian time covers the vast bulk of the Earth's history, starting with the planet's creation about 4.5 billion years ago and ending with the emergence of complex, multicelled life-forms almost four billion years later.

The Precambrian is the earliest of the geologic ages, which are marked by different layers of sedimentary rock. Laid down over millions of years, these rock layers contain a permanent record of the Earth's past, including the fossilized remains of plants and animals buried when the sediments were formed.

The Earth was already more than 600 million years old when life began. The planet had cooled down from its original molten state, developing a solid crust and oceans created from water vapor in the atmosphere. Many