It has been 65 years since the Curaçao Monument Foundation (Stichting Monumentenzorg Curaçao) was founded as part of a local initiative to save the fate of several monumental buildings on the island. Many of these historical buildings, some centuries old, had fallen into a state of decay and rapid erosion due to the salt water used to mix the mortar and plaster during the construction. In 1954, Royal Dutch Shell transferred ownership of the monumental Brievengat Plantation House to the newly formed foundation, and thus began the first of many restoration projects. The list of monuments is currently comprised of more than 120 country houses, mansions and notable historical buildings, for which the foundation has successfully preserved the unique Dutch-Caribbean style architecture specific to Curaçao. The monuments have been transformed into state-of-the-art modern buildings for purchase by companies, organizations and private residents. Throughout the years, the foundation, working closely with entrepreneurs and residents, has purchased, restored and made available for sale a significant number of historical buildings predominantly located in the Punda, Otrobanda, Scharloo and Pietermaai districts. Since 1997, Willemstad has been included on the UNESCO World Heritage List and maintaining these historical buildings will help preserve that status.