The Calle Mercaderes, connecting the Plaza de la Catedral in the north to the Plaza Vieja in the south is the main artery of Old Havana, its heart pumps a never-ending flow of tourists. Magnificently restored, it is home to some of the finest examples of colonial architecture, transformed into museums, exhibition halls and galleries. The long mural by Andrés Carillo at the start gives a foretaste of the pleasures in store as you wander down this authentic street.