Ol Doinyo Lengai is an active volcano in northern Tanzania. It consists of a volcanic cone with two craters, the northern of which has erupted during historical time. Uniquely for volcanoes on Earth, it has erupted natrocarbonatite, an unusually low temperature and highly fluid type of magma. Eruptions in 2007–2008 affected the surrounding region.

The Maasai are a Nilotic ethnic group inhabiting northern, central and southern Kenya and northern Tanzania, near the African Great Lakes region. The Maasai speak the Maa language, a member of the Nilotic language family that is related to the Dinka, Kalenjin and Nuer languages. Except for some elders living in rural areas, most Maasai people speak the official languages of Kenya and Tanzania, Swahili and English.