Lake Natron is both a salty and soda lake found at the base of Ol Donyo Lengai volcano in Arusha, north of Tanzania.
The lake lies within the Lake Natron Basin, a Ramsar Site wetland of international significance.
The shallow lake is fed principally by the Southern Ewaso Ng'iro River, which rises from central Kenya, and by mineral-rich hot springs and is a maximum of 57 kilometers long and 22 kilometers wide.
When there are high levels of evaporation the Natron (sodium carbonate decahydrate) and trona (sodium sesquicarbonate dihydrate) are left behind.
This leaves the lake with an alkalinity PH of 12 and above. This is contributed by the surrounding bedrock which is composed of alkaline, sodium-dominated trachyte lavas that were laid down during the Pleistocene period.
The lavas have significant amounts of carbonate but very low calcium and magnesium levels. This has allowed the lake to concentrate into caustic alkaline brine
It is the most important breeding site for Lesser Flamingos in the world with East Africa having 1.5-2.5 million Lesser Flamingos, representing three-quarters of the world population and most of them are hatched at Lake Natron.
Other activities within the park include: walks around the lake, streams, waterfalls, along the nearby escarpment and Ol Donyo Lengai Mountain