Tarzan and the Lost Empire (Tarzan #12)

Tarzan and a young German, working independently, find a lost remnant of the Roman Empire hidden in the mountains of Africa. This novel is notable for the introduction of Nkima, who serves as Tarzan's monkey companion in it and a number of later Tarzan stories. It also reintroduces Muviro, first seen in Tarzan and the Golden Lion, as sub-chief of Tarzan's Waziri warriors.