Evaluating an entire destination—both site and gateway—requires weighing such subtle issues as aesthetics and cultural integrity, as well as balancing good points against bad. Since simple numerical measures cannot do justice to the task, we turn to informed human judgment: a panel of 419 well-traveled experts in a variety of fields—ecology, sustainable tourism, geography, site management, travel writing and photography, historic preservation, indigenous cultures, and archaeology.

We asked panelists to evaluate just the places with which they were familiar, using six criteria weighted according to importance:

1) environmental and ecological quality; 2) social and cultural integrity; 3) condition of historic buildings and archaeological sites; 4) aesthetic appeal; 5) quality of tourism management; and 6) overall outlook for the future.

Experts first aired points of view on each destination (anonymously, to ensure objectivity). After reading one another's remarks—a variation on a research tool called the Delphi technique—panelists submitted their final stewardship scores.

The resulting Stewardship Index rating is an average of informed judgments about each place as a whole—all its many faces. Like the cards that Olympic judges hold up, our experts' scores reflect both measurable factors and the intangibles of style, aesthetics, and culture. And like an athlete, each destination has a chance to improve.

To help, National Geographic Traveler is working on a pilot project with the UN Foundation and its World Heritage Alliance to inform Cancún tourists about the Yucatán's World Heritage sites and visiting them in ways that promote better care.