At the heart of the protected area of Boeng Yeak Lom is a beautiful, emerald-hued crater lake set amid the vivid greens of the towering jungle. It is one of the most peaceful, beautiful locations Cambodia has to offer and the water is extremely clear. Several wooden piers are dotted around the perimeter, making it perfect for swimming. A small Cultural and Environmental Centre has a modest display on ethnic minorities in the province and hires out life jackets for children.
The lake is about 800m across and 50m deep, and is believed to have been formed 700,000 years ago; some believe it must have been formed by a meteor strike as the circle is so perfect. The indigenous minority people in the area have long considered Boeng Yeak Lom a sacred place and their legends talk of mysterious creatures that inhabit the waters, but don't let that put you off swimming.
The local Tompuon minority has a 25-year lease to manage the lake through to 2021, and proceeds from the entry fee go towards improving life in the nearby villages. However, developers, backed by local politicians, have long been clamouring for the sacred lands around the lake. One can only hope they are kept at bay and that Boeng Yeak Lom is preserved in all of its pristine glory.
To get to Boeng Yeak Lom from Ban Lung's central roundabout, head east towards Vietnam for 3km, turn right at the prominent minorities statue and proceed 2km or so. Motos (motorcycle taxis) charge about US$5 return (more if you make them wait), while remork-motos (tuk tuks) have been known to charge about US$10 return. It takes about an hour to reach the lake on foot from Ban Lung.