FREDERICO MAYOR, director general of UNESCO, recalls the discomfort he experienced earlier this year when he arrived in a ravaged Cambodia for a preservation mission to the famed ruins of Angkor Wat.
The civil-war-scarred southeast Asian country was a tumult of human needs, fears, and aspirations, and here was the head of the United Nations Educational, Scientific, and Cultural Organization coming to express international concern for a pile of rocks.
But it was the Cambodian people themselves who laid Mr. Mayor's concerns to rest, he says. Enthusiastic about his visit, they told him time and again, "We need to be proud of our past in order to prepare our future."
Mayor cites this experience to illustrate the importance of UNESCO's World Heritage List, which celebrates its 20th anniversary this summer. At a time when ethnic, nationalist, and economic conflicts are affecting people around the globe, he says, it is increasingly important to preserve and commemorate the natural wonders and historical sites that constitute mankind's common patrimony.
"We are at a pivotal moment in history in the march from oppression to liberty," says Mayor. "The only heritage that remains whole and which we all share is the future," he adds, "but to realize its promise we must have the memory of our past."
The preservation of mankind's common heritage is the fundamental purpose behind the World Heritage List, which to date includes 358 sites in 83 countries - ranging from ruins at the ancient city of Persepolis in Iran and the Acropolis in Athens, to Independence Hall, Philadelphia, and the Grand Canyon in the United States.
The UNESCO program seeks to identify the sites of "unique and universal value" around the world, to monitor their preservation, and to help nations develop plans for restoration and protection where needed.
Countries with registered sites commit to protecting them. That is one reason why Cambodia's Angkor temples are not yet on the World Heritage List. Deep in a UN-sponsored pacification and democratization program, Cam- bodia has not had time to develop the necessary preservation and protection plan. UNESCO officials hope the work can be completed to place the famous monuments on the list by the end of this year, however.
In addition, member states of the World Heritage convention - now numbering 127 - enlist to respect the examples of this common heritage in other countries, while making annual financial contributions for their preservation.
The list, whose creation in 1972 followed a growing public consciousness during the 1960s of threatened natural and archaeological treasures, constitutes one of the first expressions of what French President Francois Mitterrand termed, in a 1991 speech to the UN General Assembly, an international "right to intervene."
The seeds of the World Heritage List effort were planted in the early '60s, when news that Egypt's Aswan Dam would flood the famed Egyptian and Nubian monuments led to an international campaign to move them. UNESCO's then-director general, Rene Maheu, spearheaded an international drive that eventually raised more than $30 million for the monuments' preservation.
That experience awakened a realization that development and population pressures would continue to pose mounting threats to irreplaceable sites around the world - often in countries least able financially to guarantee the monuments' protection.
The idea for a World Heritage List was formally adopted in 1972 at the UN's Conference on the Human Environment. The decision to include in the list natural sites like Kilimanjaro National Park in Tanzania or the Manas Wildlife Sanctuary in India stemmed from ideas expressed by the then-budding environmental movement: the need to preserve a balance between people and their environment and the importance of nature's role in mankind's continuing development.
UNESCO will celebrate the Heritage List's anniversary with exhibits and cultural programs at its Paris headquarters, along with similar programs in more than two dozen UNESCO member countries.
In addition, Mayor decided to "give a new boost" to the preservation movement's next decade by creating a World Heritage Center at UNESCO headquarters. The idea, he says, is to better organize UNESCO's effort by placing preservation-related professionals from the scientific and cultural fields under the new center.
"We want to be better listeners to how different countries approach these issues, and to encourage a fuller range of international organizations to assist in this effort," Mayor says. One idea is for countries, organizations, or even private corporations to "adopt" threatened monuments in financially strapped countries.
Mayor and UNESCO have another good reason to commemorate the World Heritage List: It is arguably one of the UN agency's most successful ventures, and one that generally brings it positive publicity.
Even the United States, which along with Britain quit UNESCO in 1986 over charges of mismanagement and an anti-Western bias, has remained a member and strong suppporter of the World Heritage convention.
"The US is very committed to the objectives of this convention; its work and international scope are things the government has continued to wholeheartedly support," says Jennifer Salisbury, deputy assistant secretary for Fish and Wildlife and Parks in the Department of Interior, and the US representative to the World Heritage governing committee.
As the convention's largest contributor, providing about $220,000 a year, the US "is pleased to see that very little money goes to support staff," says Ms. Salisbury. "Most of the budget is for technical grants to member states for site preservation."
American praise for the program are music to UNESCO officials, who under Mayor have worked hard to change their agency's hulking, bureaucratic image, and who would like to see the US return to active membership. Ironically, however, the US comments on the heritage program come amid growing skepticism from other quarters over the convention's inability to protect the historic - and listed - Adriatic port of Dubrovnik from the Yugoslav war.
"Dubrovnik points out the [convention's] weaknesses," says Salibury, "but the attention it has received also indicates a growing interest around the world in protecting the kind of common heritage that the convention recognizes."
Mayor says he believes that being on the World Heritage List may have spared Dubrovnik even greater destruction. UNESCO sent specialists to Dubrovnik even as bombardments continued, planted the UN flag at the top of a famed tower, and began restoration work whenever the bombing stopped.
Alluding to his recent experience in Cambodia, Mayor reiterates his perspective that the idea behind a World Heritage List is not simply "to safeguard some rocks, but to bring aid and hope to those who live among those rocks.
"We must always remember," he says, "that we are not merely preserving monuments but serving mankind, whose heritage is spiritual as well."