Bond market is huge and works to raise debt for the governments and corporations. US treasury bonds are considered to the most risk free investment by investors across the world. Big corporations also issued bonds to raise debt. In the same manner local bodies also issue bonds to raise funds for its development schemes. Today millions of day traders trade the bond market and make a living. Watch the documentary below on the bond market.
https://www.youtube.com/watch?v=TGyWlKYKoq4