Visit six sovereign or quasi-sovereign nations in one trip, several small enough to cross on foot in a day ● Tour the Vatican Museums, Sistine Chapel and St Peter's Basilica in the world's smallest state ● Climb San Marino's three medieval fortress towers, still guarding the world's oldest surviving republic ● Explore Monaco's Prince's Palace and Casino Square, born from a casino built to pay off the state's 19th-century debts ● Visit Andorra, jointly ruled to this day by the President of France and a Spanish bishop ● Private wine tasting at the Prince of Liechtenstein's own vineyards in Vaduz ● Walk the ramparts of Luxembourg City, a onetime fortress now a founding EU capital