Landed in Madrid around midday, took the train into the city to find my Airbnb that was a fifteen minute walk from the Royal Palace. Spent the day exploring Cathedrals and just exploring the area on foot.
Day two I went through the Royal Palace. The lineup was about 20 minutes long, and no shade to stand in, so booking in advance would be a good idea.
The rest of my time there was spent exploring on foot. Spots like the Temple of Debod are must sees, especially at sunset.