Retiro Park is just right next to Prado. It is beautiful. There is a boating lake and you can rent a rowing boat. It is a very romantic spot, do you reckon? Just remember to wear sunscreen while rowing your boat.
As you can see from the picture, the sun is quite harsh during the day. But no worries, there are a lot of trees in the park. You can always hide in the shade and cool down instantly.
In the park, you will also find this Crystal Palace. It's a nice building entirely made of glass. It looks pretty but I find it not very functional. Inside the building, it is quite hot because it gets all the sunlight with no cover and also there is no air conditioning. I don't know what they can use this structure for as it is probably too hot to display artworks inside.