If you drive the RN10 in Madagascar from Toliara (Tuléar) to Anakao, you will somewhen pass a white sign besides the red sandy slope. The same sign stays near Befasy, a little more east in the country – but there is even no slope to drive on with a vehicle.
The sign shows the symbol of a capricorn with a fish tail, and next to it is the text „Vous franchissez le tropic de Capricorne“. It says you that you are now crossing the southern turning circle, also called tropic of capricorne. This is the southernmost circle of latitude where the sun can still reach its zenith – more exact 23°, 26′ 14,4” south of the equator. The two days this is happening are the 21st and 22nd december of each year. The tropic of capricorne is one of five turning circles that decisively split the Earth map. At the moment, it is slowely moving in northern direction, approximately 15 meters per year. Thus you can assume that the sign at RN10 in Madagascar does not show the exact turning circle, but something nearby.