Introduction to Puerta de Alcalá: Puerta de Alcalá is a neoclassical building located in Plaza Independencia, only a few meters away from the main entrance of Retiro Park. Around 1774, Carlos III appointed Francesco Sabatini to destroy and rebuild the 16th-century Arc de Triomphe, which was completed in 1778. Twice a year in spring and autumn, this is the place where flocks of sheep must pass when moving from summer pasture to winter pasture, or from winter pasture to summer pasture, and cars have to take a detour.