Barcelona is an amazing city in many ways!
It has an interesting history of urban development as well. Museu D’Historia De Barcelona released an interactive map combining 26 maps of the city throughout its history. It overlaps loads of information about urban development starting from 150 AD to 2010.
In 1859, the medieval-era walls that had surrounded Barcelona since the 13th and 14th centuries had already started to come down. In this year, the city approved an expansion plan proposed by Spanish urban planner Ildefons Cerdà, which was hailed as “one of the most revered international examples of modern planning and urban design” by Judith Urbano, an architecture professor at Universitat Internacional de Catalunya. It laid the foundations of modern Barcelona. (CityLab)
Check the website here!