La Rambla began as water. A seasonal torrent ran here, outside the medieval wall, and the bed became a promenade only when that wall came down in the 1770s; the paving still tilts toward the sea exactly as the streambed did. It is also five separate ramblas laid end to end, each with its own name. When the convents standing along the line were cleared in the 1830s, their ground passed to the city, which is why an opera house, a covered market and a large arcaded square all sit within a few minutes of each other.
The layout is the reverse of an ordinary street: the walking surface runs down the middle and the traffic is pushed to the two edges, so the plane trees meet overhead and roof the whole promenade. Flower kiosks, newsstands and portrait painters hold the centre; the bird cages that once lined one stretch are gone, and wild parakeets screech from the branches instead. It is loudest in the middle of the day, when the crowd moves shoulder to shoulder toward the water, and quietest just after dawn, when the stone is still wet from the cleaning trucks.