The Tower Bankia in Madrid was built on May 5, 2009 in Plaza de Castilla. It was originally constructed for Repsol to use as offices, but is now owned by Bankia. The tower has a unique design with only two pillars holding up three central glass cubes at the top. Engineers faced challenges with this unconventional two-pillar structure but were able to successfully measure and build it. Construction took from October 2004 to May 2009 to complete the now tallest of the four skyscrapers in the area.