I just found out that neither country claims Bir Tawil, and was wondering why that is.
The obvious reasons are that there's nothing and nobody there, and that the borders are a British construct, but is there more to it than that?
OK, so look at this map. The sticky-out bit at the bottom is Bir Tawil. To the east is a larger and more valuable piece of land called the Hala'ib Triangle.
There are two borders here. The straight one that follows the 22nd parallel and the wiggly one that dips first below (forming Bir Tawil) and then above (forming the Triangle). Back when Britain ruled Sudan and "administrated" Egypt, they set the "straight line" border in 1899, but later, in 1902, changed to the wiggly border because the tribe who grazed on the Bir Tawil were based in Egypt, while the tribe who lived in the Triangle were regarded as more Sudanese.
Nowadays, Egypt claims the border at the 22nd parallel (which puts the Triangle in their territory and Bir Tawil in Sudan) while Sudan claims the 1902 border which puts the Triangle in their territory and Bir Tawil in Egypt.
Apparently last year some American chap went and stuck a flag in Bir Tawil and called it The Kingdom of North Sudan with himself as King.
