My absolute favourite place in Lisbon is the Miradouro Senhora do Monte. It is the highest vantage point in the city and offers the most beautiful 360° panorama with breathtaking sunsets. The best thing to do is to buy a glass of sangria on the Praca Martim Moniz and then head up to the miradouro. The fantastic view makes the steep climb well worth it!
Rua da Senhora do Monte 50