The seat of power since it was built by the Spanish in the 16C, the Palacio Nacional extends its long façade along the east side of the Zócalo. Note the bell over the central door. It rings every year to accompany the "Grito de Dolorès" voiced by the Mexican President to commemorate national independence. The Palacio Nacional, which houses the executive offices, is known for its murals by Diego Rivera. Created in the 1930s, they are a magnificent illustration of the history of Mexico.