I am finding the History of Math book most fascinating. The Babylonians based their number system on base 60.
To given you an idea of what that would be like here is how we represent base 16:
1 2 3 4 5 6 7 8 9 A B C D E F 10 11 12 13 14 15 16 17 18 19 A1 B1 C1 D1 E1 F1 20...
To do the same with base 60 we would end up using the English alphabet, the Greek alphabet and still come up a bunch of characters short before we could use zero to get to "ten." Obviously it could handle really large numbers quite easily.
The funny thing is that we still use it to a limited extent today. We divide minutes into 60 seconds and hours into 60 minutes, there are also 360 (6x60) degrees in a circle.