San Marino

San Marino city exists because Mount Titano exists—the 750-meter peak provided the defensive advantage that enabled Saint Marinus's Christian community to survive Roman persecution in 301 AD and every subsequent threat for 1,700 years. The three towers crowning the summit (Guaita, Cesta, and Montale) embody costly signaling: enormous fortification investment communicating the republic's determination to resist conquest. This signaling worked—Napoleon explicitly spared San Marino ('let this small Republic live for ever'), and Italian unification respected boundaries that date to 1463. The UNESCO World Heritage historic center now converts defensive infrastructure into tourism infrastructure: the same walls that repelled invaders now channel visitors. The Palazzo Pubblico hosts two Captains Regent who serve six-month terms as co-heads of state—the world's only surviving dual executive, rotating power so frequently that no individual can accumulate dangerous authority. San Marino's service sector boom (driving 2024's 1% GDP growth) concentrates tourist spending here while manufacturing disperses to lower castelli. By 2026, the historic center's carrying capacity faces stress as tourism success threatens the authenticity that attracts visitors.