The Pirámide de Mayo (Spanish pronunciation: [piˈɾamiðe ðe ˈmaʝo]; English: May Pyramid), located at the hub of the Plaza de Mayo, is the oldest national monument in the City of Buenos Aires. Its construction was ordered in 1811 by the Primera Junta to celebrate the first anniversary of the May Revolution. It was renovated in 1856, under the direction of Prilidiano Pueyrredón. In 1912, after having undergone many modifications, it was moved 63 metres (68.9 yards) to the east, with the idea that a much larger monument would eventually be constructed around it.

The monument is crowned by an allegory of Liberty, the work of the French sculptor Joseph Dubourdieu. From the ground to the peak of the statue's Phrygian cap, the Pyramid measures 18.76 metres (61.5 feet).