South Africa's Constitution, for example, describes how the government is formed, how it is elected and how it functions. It outlines the government's powers - as well as the limits to these powers - and entrenches the rights of the people. It also sets out how the government will be accountable to the people who elect it.

The Constitution guarantees democracy by giving every person over 18 the right to vote and ensuring one voters' roll for all adult citizens, regular elections and a multi-party system of government. It says parliamentary elections must be held once every five years.

It explains how parliament and other legislatures work, how national and provincial executives are chosen and how the courts work. The Constitution also establishes six independent state institutions to support our democracy.

The Constitution also defines the features of South Africa's sovereignty - its national territory, citizenship and national symbols.

From this it is clear that our Constitution forms the basis of public life in South Africa. But it does more than just describing the nuts-and-bolts of the functioning of the state. Our Constitution also reflects the hopes and aspirations of a nation torn apart by apartheid. And this leads us to the question of what makes a constitution unique.