There is so much Plaza de Armas can offer to a visitor, beautiful cityscape, a park, a fountain, a wide range of historical buildings, churches, and unparalleled photo ops. The square, recently rechristened as Plaza Mayor (often a times the double or overlapping names are the cases with many a landmark in Lima; for instance Miraflores park got two additional names, Kennedy Park and June 7th Park) consists of the following main attractions:

1. Two arcade buildings (south side of the plaza), with the first one being the headquarters of the weekly publication Caretas. The arcades provide pleasant shelter during hot days (rain is very rare in Lima) and are lined with shops and mostly tourists-oriented restaurants (for fine dining one has to leave the historic center of Lima and head to Miraflores, Barranco or San-Isidro districts of the city).
2. On the plaza's eastern side there is magnificent Lima Cathedral, with its construction began almost 600 years ago and Archbishop's Palace of Lima (about 100 years old but built in the neo-colonial architectural style).
3. The Government Palace of Peru on its northern side (Palacio de Gobierno del Perú) dating back to the same time period as the Archbishop's Palace of Lima, the late 1920s - early 1930s. The palace is hard to take a good picture of due to the massive fence in front of it.
4. The City Hall (Palacio Municipal de Lima) and Palacio de la Union, hosting the prestigious social institution, Club de la Unión, both on the western side of the square. Both buildings are the latest additions inaugurated in the 1940s. As mentioned, even though all the yellow buildings with its wooden carved Moorish balconies resemble the classical colonial architecture, in reality they all date to the first half of the proceeding century. Each building on the plaza deserves a dedicated tour and description, however, as a whole ensemble, Plaza Mayor is one of the best known places in the city and should be visited on a broader tour of the historical center of Lima. Usually a walk from Plaza San-Martin in the south, including the pedestrian Jirón de la Unión, and the areas surroundings Plaza Mayor (Jirón Cabaya, Jirón Lampa, Jirón Callao, Jirón Junín, Jirón Ancash, Plazuela San-Francisco, and the area facing Rimac river) will give you a great sense of downtown Lima. There are lots of souvenir shops offering bottles of Pisco in various shapes and sizes, and products woven of llama, alpaca, or vicuna fur, in addition to the more standard tourist items. Exercise prudence venturing to the east of Plazuela San-Francisco; crossing Avenida Abancay will take you to Barrios Altos, not a neighborhood best-suited for solo walks, especially after sunset.