Vai Lahi, translating to "Big Lake," is a substantial freshwater lake nestled within the crater of Niuafo'ou. This impressive natural wonder sits at an elevation of 23 metres (75 feet) above sea level and features four islands, one of which remains hidden until the water level recedes. While the lake's inner walls are cloaked in lush forest, you can connect with locals who might guide you to vantage points for capturing stunning photographs.