Here for 3 days what should I do?
in 1815 brazil became the center of the empire, the capital got moved to Rio de Janeiro. Portugal became "just a territory"
so the portuguese court started crying and asked the king to come back to Portugal, he refused and gave Brazil independence then became the king of Brazil, his brazilian daughter became queen of portugal (In portugal he's known as Pedro Iv, in Brazil he's Pedro I, his daughter "Maria II")
are you going to teach me my country's history? You don't even know who Kubitschek is
Portugal was never a Brazilian colony cause like you just said they got a queen still making it a independent country and the main Portuguese empire moved to Brazil when Brazil was still a colony and then became independent making it no longer a colony of the Portuguese empire but Brazil didnt own Portugal because it had a ruler making Portugal still independent
Check out the beautiful architecture of the city, there's a multitude of bars where you can go and have fun, you should go to a Fado place so you hear our signature music
If you are just staying in Lisboa besides the beautiful buildings and the night life there's not much to do, you should go to Sintra and check out the "Palácio de Sintra"
There's a multitude of travel guides that say things that you might want to se, I dislike Lisboa a lot so I can't help that much xd
Check this travel guide to see stuff to do: https://www.youtube.com/watch?v=N8bHCHl8X_0
Hope you enjoy your stay in our country, and in the future check out other places of Portugal ,our small country has a lot to offer :)
A "must" for me was visiting Castelo de São Jorge which gives you a good view of the city.
The rest could be covered with the video that #7 posted.
Portugal is such a beautiful country and it isn't that big so you can move to different towns. I visited Porto and -for me the best part of the trip- Leiria and its surroundings. A lot of "medieval" stuff to check out.