This map, published by Carlos María de Castro in 1861, forms part of the descriptive report on the preliminary draft of the expansion of Madrid.
The map shows the preliminary draft as it was at the time of its approval in 1860, after three years of work since the Minister of Development, Claudio Moyano, proposed its study in 1857. In the following decades, the widening project would be modified on multiple occasions, as early as 1964, when the number of floors was increased from three to four and the number of planned parks and gardens was reduced.
The areas that were built most faithfully to the original plans were the Paseo de la Ronda, now known as Madrid's second ring road, and the Salamanca district, in the upper right-hand corner of the map. Many other things changed significantly, perhaps most notably the continuation of Paseo de la Castellana, which in the preliminary design was expected to lead to a large park starting at Plaza del Obelisco, now known as Plaza de Emilio Castelar.
Sources
Español 
English (UK)