The last section MacLehose Trail is the lengthiest one, crossing almost half of Tai Lam Country Park and extending to Tuen Mun Town. Kat Hing Bridge is the intersection of streams and was the main access connecting Yuen Long to Tsuen Wan. There used to be seven small crossing bridges, which the residents called “Tsat To Ho”. It was not until 1868 that the people living there pitched in and built Kat Hing Bridge, which was revamped in the 1950s when Tai Lam Chung Reservoir was constructed. In the vicinity of distance post M173, you will walk through a small crossing bridge, where the damselfly, Indochinese Copperwing, can even be seen. Along the north side of Tai Lam Chung Reservoir, constructed in 1957, the reservoir was the first reservoir in Hong Kong after World War II. The 45-metre high main dam crosses Tai Lam Chung Valley and is the largest of the New Territories valley reservoirs. Since the valley where the reservoir is located is a hill belt, many islands were formed after water is stored, hence the green “Thousand-Island Lake of Hong Kong” of today.