a superlative natural phenomenon related to its refuge function for relict and world-unique freshwater species, and its rich bird life. The lake became part of a mixed Natural and Cultural World Heritage Site in 1980 when the city of Ohrid in Macedonia was also designated with UNESCO status for its architectural, artistic and religious values. Concern over current and potential deterioration of the World Heritage Site prompted invitation of a joint Reactive Monitoring Mission by the World Heritage Centre, IUCN and ICOMOS in April 2017, which identified a wide range of pressures including from transport infrastructure, traffic, tourism developments, overfishing, sewerage, solid waste disposal, invasive species, both legal and illegal construction, and management of water levels. The mission report devised 19 recommendations for Macedonia, which were incorporated under Decision 41 COM 7B.34 of the World Heritage Committee at its 41st Session in Krakow, Poland in 2017. In May 2019, the UNESCO World Heritage Centre expanded the World Heritage Site to the Albanian side of the lake. In addition, draft Decision 43 COM 7B.36 was released recommending for the Ohrid region, including Lake Ohrid, to be placed on the List of World Heritage in Danger during the 43rd Session of the World Heritage Committee in Baku, Azerbaijan. This position aligns with IUCN advice. In its analysis and conclusions, the World Heritage Centre observed threats to Lake Ohrid from "decreased water levels, uncontrolled discharge, water pollution due to inadequate wastewater treatment systems leading to evident eutrophication at the mouths of intake rivers, heavy pressures from tourism, and extensive uncontrolled urban development and inappropriate exploitation of the coastal zones." It also observed that the majority of recommendations from the 2017 Reactive Monitoring Mission had not been implemented. Science and research Due to its size, accessibility and species richness, Lake Ohrid is extremely well-suited to the function of a natural laboratory. Deep sediment cores augmented by diverse ecology in the present day offer an extensive archive from which to understand the history of its region over the past 1,200,000 years. Research to date has investigated biodiversity processes, the interplay between geological and biological evolution, the birth of European agriculture, and investigations of regional climate and environmental conditions over hundreds of thousands of years. Among other contributions, such research has delivered the first empirical evidence for niche-based assembly processes from a natural system and demonstrated the establishment of dynamic equilibrium in an isolated ecosystem during