Plaza San Martín, Public park in Retiro, Argentina.

Plaza San Martín is a public park in the Retiro neighborhood of Buenos Aires, covering three hectares and bordered by Libertador Avenue and Santa Fe Avenue. It sits at the northern end of Florida Street and links several main roads with tree-lined green spaces.

The Cañete brothers built the octagonal brick bullring here between 1800 and 1801, seating 10,000. From 1812 the barracks on the slope housed San Martín's Mounted Grenadiers, who left from here for San Lorenzo; the bullfights were banned in 1822. In 1883 the fort, bullring and other buildings were demolished to create the plaza, laid out by Charles Thays from 1889.

The square was renamed in San Martín's honour in 1878, on the centenary of his birth; the equestrian statue by French sculptor Louis-Joseph Daumas was commissioned in 1862. Bronze plaques near Santa Fe Avenue recount the site's history. In spring 2009 the park hosted the United Buddy Bears exhibition, over 140 painted bear sculptures two metres tall, its first showing on the American continent.

The park is open daily and offers shaded paths beneath the trees that provide relief during warm weather. Retiro train station sits right next to it, making the park easy to reach on foot.

More than 350 trees, including jacarandas, tipas and palo borrachos, grow here and form one of the largest urban green areas in Buenos Aires. When the jacarandas bloom in spring, purple flowers cover the paths.