sentences:  This area contains the large Plaza de Colón.This plaza commemorates Christopher Columbus, who was responsible for ushering in the Spanish imperial golden age of the 16th and 17th centuries.It is within walking distance of the main cultural and commercial areas of the city, such as the Prado museum, the expansive Parque del Buen Retiro and the business center on the lower part of the Paseo de la Castellana.