The highest capital in Asia is Thimphu at 2,648 m (8,688ft). The highest in Africa is Addis Ababa at 2,355 m (7,726 ft), followed closely by Asmara at 2,325 m (7,628 ft). The highest in North America is Mexico City at 2,240 m (7,350ft). But some of the capital cities in South America easily exceed all these in elevation. The highest are

Sucre 2,810 m (9,214 ft).

Quito 2,850 m (9,350 ft)

La Paz 3,650 m (11,975 ft)

Geography buffs will note that that there are two cities from Bolivia included in this list -- the reason for this is that the functions of capital are split between Sucre and La Paz. But, whatever the administrative and political arguments, it is clear that South America contains the world's highest capital.

More Info: en.wikipedia.org