Cherry Picking The Diamonds From The Stock Market

Do stock market indices have a base value?

Right now the FTSE stands at 5744.9 and the Dow Jones stands at 11023.4. What were the figures when the indices just began? Did they start at 0?
Or (given that the indices go down as well as up and that a negative value would not be possible) did they start at a fixed figure like 1000?

Most stock indexes started with a base value of 100, there are a few that started at 10.