I started my first sightseeing day in Madrid with a walk in Parque del Buen Retiro which was established by the Spanish monarchy in the 1600's and given to the public in late 1800's. It is a labyrinth of paths.
Near the center of the park is the Palacio de Cristal which was built to house botanicals but is now used for various exhibits. I got there before it opened but in time to catch some great sun.
Then it was time to queue up for the Museo del Prado. No pictures allowed inside fortunately; it was crowded enough without lines of selfie photographers.
After three hours of the crowded museum I went for another nature stroll in the Jardin Botanico. 29 acres and two huge greenhouses of trees, shrubs, flowers, edibles. I couldn't begin to see it all.
Sunflowers loved the 95 degree heat. Me? Not so much.