On Maclehose Trail Stage 1, you are walking around half of the High Island Reservoir (萬宜水庫). On Sai Kung Man Yee Road, you can get a full view of the reservoir from different angles. In clear weather, the water is jewelry blue.
High Island Reservoir is the largest reservoir in Hong Kong, holding water of approximately 273 million cubic meters. The construction work began in 1971 and it took 7 years to complete.