Which two regions are Belgium 's largest ?
The constitutional system of Belgium grants the Walloon Region its own legislative and executive powers in the fields for which it is competent : agriculture and rural renewal development of the territory and town planning economy and foreign trade employment and vocational training the environment , water and nature conservation housing local authorities , subsidized works and sports infrastructures scientific research , new technologies and energy international relations health and social affairs tourism and heritage regional transport , mobility and public works .