After Tanzania, then called Tanganyika, became independent from Britain in 1961, the country's leader, Julius Nyerere, made Swahili the national language to unite its people.
Walter Bgoya tells Ben Henderson about his conversations with Nyerere and how the policy changed Tanzania.
In 1969, a Peruvian farmer called Gustavo Del Solar received an unusual assignment - finding a bird called the white-winged guan that had been regarded as extinct for a century.
After years of searching, he found the bird deep in Peru’s wilderness in 1977. He then made it his life’s mission to...