I've visited Lisbon a couple of times, but never managed to venture much further than the city centre. This time though we stayed in an area called Belém, which I wasn't familiar with before, but will maybe become a favourite.
It's a couple of miles outside of the centre of Lisbon, but has good transport links, with a nearby railway station, and trams that take you into the centre. It's also on the riverbank, so is really good for restaurants, and parks.
One of the most impressive monuments is the Padrão dos Descobrimentos, which celebrates Portugals age of discovery during the 15th and 16th Centuries. Portugals history of exploration and colonialism is very much embodied in this part of Lisbon, placing you in the centre of history.
We had a great time exploring the old monastery, a brilliant art gallery, which we only had time to explore half of, and Belém Tower. The Tower of Belém, was built in the 16th Century and was thought of as the 'Gateway to Lisbon', used as an embarkation point for travellers and explorers. It certainly would have let you know that you had arrived somewhere important!
I was very impressed by the "Monument to the Overseas Combatants", which commemorates the lives of soldiers who died during the Portuguese Colonial War, between 1961-74. Being British, I wasn't aware of this part of history, in which Portugal fought to retain its colonial influence in Africa. It was a peaceful and quiet place to learn a little about the world.