Based on the former Spanish Royal Collection, the Prado is a beautiful old castle with more than a thousand fascinating works on display. One of the world's premier art galleries, the more than 7000 paintings held in the Museo del Prado’s collection are a penetrating look at the celebrated history of Spanish art. Prado offers free entrance from 6-8 weekdays, 5-7 on Sundays and holidays. This is often the busiest time and entrance to temporary exhibitions is not included.
And the Prado museum is one of the museums you have to see in your life, great collection