A Book of Centuries is a concept developed by the educator Charlotte Mason. It is a timeline of the world that fits into a book format. Every time you learn about an important person, event, invention, etc. in history it gets put into the Book of Centuries. This makes for a very easy way to see how what you're learning in all school topics relate to one another. I was not happy with any of the available book designs, so I created my own.
Most spreads are a single century, but very early history is more:
Infinity -> 8001 BC
8000 -> 6001 BC
6000 -> 4001 BC
4000 -> 3001 BC
3000 -> 2501 BC
2500 -> 2001 BC
2000 -> 1901 BC
... from here on out, each spread is a single century.
In the middle we have:
100 BC -> 1 BC
1 AD -> 100 AD
The book ends at 2100 AD.