Buenos Aires, Argentina’s big, cosmopolitan capital, is known for its European atmosphere, passionate tango and vibrant nightlife. Its center is the 16th-century Plaza de Mayo, lined with stately buildings including Casa Rosada, the iconic, balconied presidential palace. In Microcentro, Florida Street is the main shopping thoroughfare, leading to Plaza San Martín, a busy park that was once the site of a bullfighting arena.