On a budget, Plaza de España still earns its price.
Free
Before its 2021 overhaul this was a tired, traffic-choked square you crossed quickly; the redesign buried the cars and turned it into a genuinely usable green seam linking Gran Vía to the Temple of Debod. The Cervantes monument with bronze Quixote and Sancho still anchors it, and it now works as a stroll-and-sit space and the natural walking line toward the city's best sunset at Debod.