Every city needs its green spaces - somewhere to go for a walk, ride your bike, have a picnic, read a book, lie in the sun, play football, let the kids run around, feed the pigeons...
In the case of Seville's Parque Maria Luisa, as well as all that, you can climb a tower with a waterfall; rent a bike-type vehicle for four people, or a go-kart, or a rowing boat; go to an archaeological or ethnographical museum; and admire the amazing Plaza de España with its majestic fountain, incredible tile-work and map of each province.
I often go for months without visiting Seville's largest park, before returning and remembering how much me and my family love it.
You can also visit the Jardin Americano, with plants from the Americas; and the Jardines del Guadalquivir, an interesting garden with many different areas - ponds, rose gardens, sunken areas, a maze, sculptures - great for kids. Both date from Expo 92, and were refurbished in the last few years after decades of neglect; the gardens are not well-known, so they're usually quiet.
Now that the sun is out, the skies are clear, and days are warmer, it's time to head for the great outdoors!