WORLD HERITAGE is big business, bringing hordes of tourists to poor countries that can use the jobs and the cash. It can also overwhelm the very sites it is designed to protect with all the less-savory aspects of mass travel, from chain hotels and restaurants to the impact of thousands of sport-shoed feet treading on fragile ground.

But World Heritage can also be an odd business, giving recognition to traditions (like premodern tribal dances and giant French family meals) that might have little aesthetic value to any group except the one that practices it.

Whatever the merits, the United Nations Educational, Scientific and Cultural Organization (Unesco) has embraced the concept. In fact, Unesco loves heritage so much that it has created two treaties to enshrine it.

The first, the World Heritage Convention, dating from 1972, builds on the notion of the United States national parks system, which was set up to defend a wild landscape before it disappeared. The second, the Convention for the Safeguarding of Intangible Cultural Heritage, was introduced in 2003 to defend traditions, not places, and is more controversial. Some 188 nations have ratified the first convention. To date, there are 725 cultural, 183 natural and 28 properties combining the two, in 153 countries. The World Heritage list represents a catalog of marvels. Italy, needless to say, includes the Leaning Tower of Pisa (the whole Piazza del Duomo, to be fair) and Venice and its lagoon. Jordan has Petra and Wadi Rum. France even lists the banks of the Seine.