Ildefons Cerdà i Sunyer (December 23, 1815 - August 21, 1876) was a Catalan civil engineer active during the mid-19th century.  Cerdà was born to a wealthy family in Centelles and studied engineering in Madrid.  He moved to Barcelona in 1848 and, appalled by the city's sunless cramped streets and horrific sanitary conditions, lobbied for and successfully instituted a complete urban renewal.