One of the largest city parks in the Western Hemisphere measuring 1,695 acres, the Bosque de Chapultepec is compared to Paris's Bois de Boulogne or New York City's Central Park. Besides acting as a green lung for the giant metropolis that surrounds it, the park houses nine museums, a zoo, amusement parks, lakes, fountains, the 18th century Chapultepec Castle (once a summer retreat for viceroys and Presidential residence) and the Los Pinos complex - the current presidential residence. The most popular day is Sundays when museums are free.