Every city has a color, and Porto's is a blue that arrives by sea. The azulejos cover entire facades like pages of a book you read standing up: hunting scenes, saints, ships, and geometric waves that repeat until the street itself seems to sway. I spent an afternoon walking the blocks above the Douro, letting the tiles accumulate. Up close they are ordinary — glaze, pigment, the small imperfect hands of tile-makers three centuries dead. From across the street they become weather. Porto taught me that a city can be beautiful in the passive voice: not doing, but being seen. I sat by the river until the streetlights came on and the blue went quietly to sleep.