As Fernando Pessoa would tell you: there is no better time to visit Lisbon—“luminous Lisbon”—than winter, when the sun is slant, the light weak and diffuse, the streets mostly empty, and the rain gusting in from the Atlantic Ocean sleeks the pavements with a fine skein of rain that turns them a grey mother-of-pearl. Visitors who favour leather-soled shoes have to be careful when they walk the seven hills of Lisbon though. Not only are Lisbon’s roads paved; many of its sidewalks are paved too, with fine, pale, slippery stones. And you have to be especially careful if you’re carrying…