Palacio de Cibeles is a stunning building located near Gran Vía. It was originally built as a post office in the early 20th century and is now the headquarters of the Madrid City Council. The building is known for its beautiful architecture, featuring a mix of Neo-Gothic and Art Deco styles. Visitors can explore the interior of Palacio de Cibeles, which houses several exhibition spaces and a rooftop terrace with panoramic views of the city. It is also home to the Madrid City Hall, where you can learn about the city's government and history.