Southern Passage

The Southern Passage is an isthmus connecting the two continents, Tamar and Galedon. It is a narrow one, about 400 km long and 15-100 km wide, the narrow part being about 200 km.
It is a route that is sometimes used by people, but crossing it is very dangerous as it takes a long time and there is no proper shelter from the elements. The winds are harsh and if the waves are high they might splash onto travellers too. The terrain is mostly sand and rocks, with only small hardy plants growing.
On both north and south sides there are unhabited islands, that are the homes of lots of birds and other marine animals, like seals.
When the sea level is high, the isthmus might be covered in water and be unpassable, or it may require long distances of wading. On the contrary however, when the sea level is low, the passage is much wider and the nearby islands might be connected by land too. The sea only gets deeper when past the islands.
Most folks who need to get from one continent to another choose to do it by boat, which is a lot safer. The southern seas are quite safe, and with a good sailboat one can sail along the north side of the Southern passage in about 1-3 days, versus 16-20 days walking in difficult conditions.
The road that goes along the isthmus is small and narrow, wide enough for a single horse but not a carriage. It is uneven and rocky at places, and