In the richest neighbourhood of Barcelona the square meter costs as five times as in the poorest, according to the City Council data (I, II). While not surprising, this chart reflects a city where living in a different neighbourhood could mean to have a decade less of life expectancy.
The blue neighbourhoods are above the average rent in the city (100) while the orange ones are below.
This chart is based on the Mike Bostock’s scatterplot example with three additional features: