Today cross the Rio de la Plata (River Plate) to Colonia del Sacramento by ferry (approximately 1.5 hours). On arrival, enjoy free time to explore this charming colonial city, known as the oldest in Uruguay. The World Heritage-listed Barrio Historico (Old Quarter) is a great place to start. Stroll down the cobblestone streets and rub shoulders with locals as they sip their yerba mate (tea). Listen to the noisy parakeets in the Plaza Mayor, or comb Colonia’s small museums. For great views over the city, climb to the top of a 19th-century lighthouse that’s still in operation.