9. South Korea
South Korea shares its border with North Korea which has an extremely powerful army at its disposal, and hence, is a constant threat to South Korea. But, its offensive neighbour is not its only problem. To meet the increasing armament of China and Japan, South Korea has been increasing its defence expenditure, which is now $34 billion. SEE ALSO: 10 Weird military vehicles of World War II (With Pictures)
It maintains a large army of over 640,000 active personnel and 2,900,000 additional personnel in the reserve, alongside the 6th largest air force with 1,393 aircraft, as well as a small 166 ships. The country has about 15,000 land weapons, including rocket systems, as well as 2,346 tanks. It routinely participates in military training with the US.