I always as this question...
When the Great Apes were separated, how many generations did it take for them to evolve into separate species such as orangutans, gorillas, chimpanzees and humans that were incapable of interbreeding with each other and producing offspring that could also reproduce themselves?
The timescale on the left is in millions of years. "Pan" is chimps and bonobos. "Pongo" is the orangutans.
A closeup of the "homo" lineage: