Madrid is my favorite city, and probably my favorite place on Earth, but we're here during the height of summer and it's about 105F every day with a light breeze at most. Fresh air and open spaces are...crucial in weather like this.
Enter Casa de Campo. Originally the royal hunting grounds, today's less...feudal environment has seen this massive area converted to a public park on the western side of Madrid.
One of the best parts is the sporty ride on the Teleférico de Madrid from the Parque del Oeste into Casa de Campo -- an 11 min ride that carries 72 cars 8,061ft.
Casa de Campo is kind of arid, with big trees and light brush scattered around, and crisscrossed by trails that, if it weren't a million degrees outside, would be amazing for a run or bike ride. Less fun, but still interesting, it was also the front line of the Siege of Madrid as Republican Spain held off the Francoist armies for just over two years.