In many countries you need a visum, it depends of why you travel : toerist?, business?, time? …..
Depending of your residence, it can be different.
For Belgian citizens, when you travel outside Europe/Schengen : you need an international passport.
You need a visum for :
Belarus – 2018 : if you enter and leave the country via Minsk and you stay no longer than 5 days : NO
Russia – 2018 : YES
SaudiArabia – 2018 : YES
Latvia – 2018 : NO
UK – 2018 : NO
Canada – 2018 : NO, but you need an Electronic Travel Authorization ( ETA )
Ireland – 2018 : NO but you need to pass the pasport control
Greece – 2018 : NO
Portugal – 2018 : NO