Documentary about the Wallace line
Invisible line separating two animal regions from each other
Here is a mini-documentary about the imaginary "Wallace Line" that goes through Malaysia's Indonesian islands. It splits up two different animal regions - the Oriental on the west side and the Australasian on the east side.
The Wallace Line is an imaginary line between Indonesia and Australia with associated archipelagos, which divides the two zoogeographic regions of Australasia and the Oriental. The zoogeographic area closest to the east of the line is called Wallacea.— Wikipedia on The Wallace Line