Describe your idea:
Gather together all known historical records, starting with the oldest, and cross-link them. (Maybe crowd-sourced? Wiki entry for every person or event in history?)
Births, deaths, marriages, legal records, etc would be a good place to start, then add in tax and military ledgers, maps and so forth.
This creates a national geneaology database with a context.
eg John Smith, born 1627, Lincoln, died 1665, London of plague, wool merchant, also served on HMS Elizabeth 1640-1647, married Mary Jones 1650, etc. Similar data available for children and parents, plus images of ship, financial records, etc.
What problem does it solve?:
1. Puts historical data into a bigger context and creates statistics which may be relevant today.
eg it becomes possible to track:
migration to cities and economic impacts such as changing land values or labour costs over centuries
large scale effects of events like black death or war
agricultural output vs climate
2. Identify change points, and their impacts, such as improved plow in 17th C
3. Track who is related to who, and enables family histories to go back further in more detail, with historical context.
4. Helps research genetic variations, diseases, etc.
Type of idea: A piece of infrastructure or an API