The Monument to Felipe IV in Madrid's Plaza de Oriente has a remarkable backstory. The equestrian statue shows the king balanced on his horse's hind legs alone. It's a feat of engineering that required help from an unlikely source: Galileo Galilei. When sculptor Pietro Tacca faced the physics problem in the 1640s, Galileo calculated how to distribute the weight, making the front hollow and the back solid bronze. The result has stood for nearly four centuries.

Felipe IV also rejected the original face, finding his likeness unflattering. A more idealised version based on a court portrait replaced it. The statue was later thrown out by French troops during Napoleon's occupation, returning only when Queen Isabel II reorganised the plaza.

VoiceMap's self-guided audio tours use the monument as a starting point to explore Madrid's layered past, tracing how Habsburg ambitions shaped the city and suppressed its Muslim origins.