<human>:  What is the best thing to do in Madrid on a Sunday?
<bot>: The best thing to do in Madrid on a Sunday is to explore the city's historical attractions, like the famous Prado Museum and the Royal Palace. You can also visit some of the city's famous parks, such as the Retiro Park or the Casa de Campo. Take a leisurely afternoon stroll down the Gran Vía, or take a stroll through the bohemian streets of La Latina. Finally, end your day with a traditional tapas dinner in one of the many lively plazas.