(Lisboa, Portugal) I spent a few hours wandering around the Castle of São Jorge today. This was my first experience spending any significant amount of time in a medieval castle, and I walked away impressed with the architectural finesse associated with building such a massive fortification.
The castle walls and towers you see in the picture rise over 30 feet in the air, and I was hard pressed to imagine exactly how an attacker might scale these barriers.
The fortress also served as the royal palace of Portuguese monarchs, at least until Manuel I built the new palace by the Tagus River, Ribeira Palace. The facility later served as a barracks and as a prison, though it fell into disrepair after the 1755 Lisbon earthquake.