四次元年表for mobile

``Four Dimensional Chronology'' is a project in which users cooperate to build a database that covers all historical events, regardless of field, from the beginning of the universe to the endless ``now''. We aim to correctly display temporal and spatial distances by requiring not only "when" but also "where."
This app does not collect any personal information about you, nor does it track or use any information on your device. The historical information you register will not be linked to you. There is no record of what you register or what you search for.