Chronyas is a single, zoomable timeline of the history of the Earth, from its formation 4.54 billion years ago to today. You can drag through time, zoom from billions of years down to a single day, and open any event to read about it.
The background changes with the era: each of the thirteen eras, from the molten Hadean to the contemporary world, has its own landscape, painted and rendered by Chronyas itself.
How events are chosen
Events come from Wikidata, the open knowledge base, and from a short list of milestones that we date by hand, such as the origin of life, the first tools or the invention of writing. Each event is ranked by importance, which is based on how many language editions of Wikipedia have an article about it. We use Wikipedia only to count; none of its text is copied.
Very large groups, such as battles, towns and births, are thinned out so that the timeline stays readable. Dates are shown no more precisely than the source allows: an event known only to the year is shown as a year, and a deep-time event is shown as millions of years ago.
How the descriptions are written
Most descriptions are assembled by a script from the dates, places and short descriptions in the data. Some summaries, mainly for the most important events, are written with AI assistance from verified data. They are checked automatically: a summary is rejected if it contains a year or a figure that is not in the source data. Summaries written this way are marked on the timeline.
Automatic checks are not the same as an expert review, and some dates in open data are disputed. If you find a mistake, please tell us on the contact page and we will correct it.
Sources and licences
The data sources, with their licences, are listed on the sources page.
Who publishes this site
The publisher is identified on the contact page.