What long valley extends along the eastern side of africa on the valley floor are several long slender lakes?

The valley that runs through East Africa is called the East African Rift System, also known as the Afro-Arabian Rift Valley. This rift represents a narrow zone that is a developing divergent tectonic plate boundary, where the African plate is in a process of splitting up in two separate tectonic continental plates, called the Nubian Plate and Somali Plate.