In 1930, in what was then French Equatorial Africa, a 600mm gauge railway was opened between Zinga and Mongo, a distance of 7.5km. It functioned as a portage route, bypassing rapids on the Ubangi river.
The line was destroyed by the conflict leading up to independence in 1960. Extensive remains can be seen, including two derelict steam locomotives and some rolling stock. The remains have been added to a tentative list to be considered for UNESCO World Heritage status.
Flag image from CIA World Factbook