Lisbon was flattened on the morning of 1 November 1755, All Saints' Day. An earthquake at about 9:40 was followed by a tsunami that swept up the Tagus and a fire that burned for hours, and the city never quite got over it. The Marquis of Pombal rebuilt the center as a strict grid, the Baixa, in one of the first earthquake-resistant designs. Alfama on its hill survived and stayed a maze. Walk from one to the other and you cross about 250 years of urban planning in ten minutes.
Lisbon doesn't try to look new. Tiled facades are cracked, trams from the 1930s still grind up the hills, and the river is wide enough to pass for a sea. It also punishes bad planning: the hills are steep, the cobbles are slippery when wet, the big sights close on different days, and the palaces of Sintra sell timed tickets that run out. Five days is the right length: four for the city, one for Sintra, and evenings left for what Lisbon does best, which is sitting somewhere with a glass in hand while someone sings.
The plan runs Baixa, Chiado and Bairro Alto on day one, Sintra on day two, Belém and LX Factory on day three, Alfama, the castle and fado on day four, and the Gulbenkian museum, the park and a last sunset on day five. Start on a Wednesday if you can: nothing you want is shut that way, the flea market falls on a Saturday and Sintra on a weekday. More on the country is on the Portugal page. If you travel between November and March, read the winter tip: it rains, and the sun sets before 5:45 pm.