This site, placed on the World Heritage List in 1980 under criterion (iii), is one of the monuments concerned by the safeguarding campaign launched on behalf of Malta.
In 1979, with financing provided by the Fund ($2,300), an expert was dispatched to study the problems of climatology and hydrology and to advise the competent authorities regarding the equipment needed to remedy them.
A request was made to the World Heritage Fund in 1981 for the purpose of securing air-conditioning equipment ($3,570).
When the Working Croup established under the International Campaign visited the Hypogeum in April 1983, they noted the problems caused by the high humidity, including the growth of algae on the walls which were damaging the wall paintings, and recommended that the services of experts in hydrology and in ventilation be provided, that modifications be made to the lighting system, and that the buildings overhanging the Hypogeum be demolished and a new entrance built.
The authorities have been monitoring the temperature and level of humidity in the Hypogeum over a period of 3 1/2 years with equipment provided by Unesco. A $2,700 allocation from the Fund served to send an expert in hydrology who visited the Hypogeum in December 1988 to help determine the origin of the water infiltrating the Hypogeum; his preliminary conclusions were that the main source was groundwater coming from the supply water system and, in particular, used water. Further tests and analyses are being carried out. The lighting system has been modified, with the result that the algae are not developing further. In addition, the special account opened to finance the campaign enabled two experts to be dispatched in 1990 to examine the ventilation system ($8,360); _their report can be consulted in the Secretariat. French experts who worked at Lascaux visited the Hypogeum in June 1990 and advised on the question of ventilation, visitor control and on the new entrance for which architectural plans have already been prepared. The buildings overhanging the Hypogeum have already been demolished and it is now urgent to construct the new entrance to provide adequate protection for the monument.