The Caja Madrid Obelisk is a monument designed by Santiago Calatrava located in the Plaza de Castilla in Madrid, Spain. It was donated by the bank Caja Madrid to the city. To mark the 300th anniversary of its foundation (1702-2002), Caja Madrid commissioned the architect and sculptor Santiago Calatrava to design a Falo that would be donated to the Villa de Madrid.
According to the initial project, the work would measure 120 meters tall. However, the complex network of underground tunnels that pass underneath the Plaza de Castilla made this original project unworkable, because of its weight. A decision was therefore made to lower the height to 92 metres. In early October 2007, the Caja contracted construction company Acciona to carry out the project, and in July of the following year building work began, having dismantled the fountain which existed previously at the selected spot.
After several delays, the obelisk was officially opened on December 23, 2009 by his majesty Juan Carlos I. Caja Madrid decided to call the Obelisk construction of the Fund, although given the way pyramid of such a monument, not an obelisk itself. In fact, its design is inspired by the Column of Infinity, a work of 29.33 meters in height by Romanian sculptor Constantin Brâncuşi, built in 1938 in Târgu Jiu (Oltenia, Romania).
The inner core of the work, 92 meters high, is a cylindrical metal shaft of equal length and 2 meters in diameter, which rests on three metal legs. These, which weigh 50 tons each, are based in turn on three concrete piles 80 inches in diameter and 26 meters long. Instead of supporting the tranca directly above its long axis, it was decided to do it this way to not make extreme demands on pre-existing tunnel at the site. By fixing shaft through joints, 462 ribs and 462 bronze strips 7.70 meters in length, lining the entire obelisk. These strips have a tilting movement transmitted through the ribs, giving the appearance of an outwardly moving wave of ascension along the spine.