The buses numbers 21 (until the stop NATO, airport not included) and 22 are free for the workers of the European Institutions (including trainees), upon presentation of their badge to the driver.
Something I noticed as a difference from Portugal was the shortage of ATMs around the city. As soon as I realized that, I identified already two or three of them that were either close to my house, or on my way to work, or near the supermarkets I visited regularly and I would take some more money than what I usually carry with me, just for the case that I might need it and not have an ATM around. It is common that you see, especially during the night, but at daytime too, queues of people next to ATMs, because they are indeed not very abundant. It happened to me that my card was not working in the terminal of a taxi and we had to go around the city during the night looking for an ATM for me to withdraw some cash (because during the night some of them don't allow withdrawals, or don't allow that you enter the bank, when the ATM is inside). So make sure you always have some reserve money with you, in the event you may need it (this taxi thing ended up costing me an extra 15€!).
As a trainee in the EC, you have the right to take 2 days of vacations per month, so you have a total of 10 days to take during your traineeship. Plus, there's also several holidays during each session. Check the calendar for the EC and see which days are holidays (for example, the Spring session gets several days during Easter and the Winter session gets various days for Christmas and NYE's as well), because that may be a good time to return to your country or to do some trips around. If you add to these the vacation days you are entitled to take, you have more than time to travel around and Brussels, being so centrally located, is an excellent place to make use of this possibility.
A great place to gather on the sunny days is the Bois de la Cambre. You'll find lots of people there, riding their bikes, jogging, having a pic-nic, playing with their children, walking their dogs, etc. The place has a lake and an immense green area, so it's great to just spend some hours laying there in the sun.
Pay attention to all the
events that are happening in the city. I feel like every week there are conferences, seminars, festivals (of music, cinema, documentary films, theatre), activities, open days at museums and galleries... and most of them are free, or for a reduced price. Check the Facebook group for your traineeship session, as well as the
Stage Committee website, as people usually post there about the things they find about. Look for other Facebook pages about Brussels, where you can be updated about what's going on, so you don't miss a thing. This is a city that if you want to be busy everyday doing things, you can. There's always so much going on!
Pay attention when
recycling! In Brussels you have to buy specific bags depending on which garbage they hold (blue for plastic, yellow for paper and white for general trash). You can find them easily in rolls with lots of them in every supermarket and they are cheap. Then you have to see what are the collection days for what type of garbage in your commune and put that trash outside in the evening of such day. Usually it's a good method if you look around in your street and neighbourhood and see many bags of the same colour outside, then you know you can put that one out. If you put a bag out on a day that it was not supposed to, or if you put on that bag some garbage that doesn't belong to it
(yes, sometimes they check!), you can get
a warning or even a fine.
Be prepared for
weather changes. Last year, at this time, it was snowing and negative degrees. This year it has been sunny and temperatures reaching almost 20 degrees! So the weather in Belgium is really unstable... enjoy the sun while you have it, but never discharge your winter coat and your umbrella, as you may need them even in July
(happened to me last year!).