In the city of Cuzco in Peru, what is the name of the main central square that forms the historic heart of the city?

Introduction / Context:
This question belongs to cultural and urban geography of South America. Cuzco, located in Peru, was the capital of the Inca Empire and is now a major tourist destination and World Heritage site. Like many Latin American cities, it has a main square that serves as the historic and social centre. The question asks you to identify the name of this central square, which appears frequently in travel and history references.

Given Data / Assumptions:

• The city referred to is Cuzco in Peru.
• The options include Plaza de Armas, Machu Picchu, Catedral de Santo Domingo, and Barrio de San Blas.
• We assume standard tourist and historical descriptions of Cuzco.
• The term main square refers to the central open plaza around which important buildings stand.

Concept / Approach:
Many Spanish colonial cities in Latin America have a central square named Plaza de Armas, where colonial authorities organised military parades and civic ceremonies. Cuzco follows this pattern. Its main square, formerly an Inca ceremonial centre and later redesigned by the Spanish, is called Plaza de Armas. Machu Picchu, although strongly associated with Cuzco, is a separate ancient city located in the mountains. Catedral de Santo Domingo is a cathedral building on the square, not the square itself. Barrio de San Blas is a neighbourhood within the city.

Step-by-Step Solution:
Step 1: Recognise that the question focuses on the main square in Cuzco, not on nearby ruins or separate sites. Step 2: Recall that many Peruvian and Latin American cities use the name Plaza de Armas for the main city square. Step 3: Connect Cuzco with images of a large open plaza surrounded by colonial buildings and churches, which is known as Plaza de Armas. Step 4: Identify Machu Picchu as an archaeological site and separate ancient city located some distance away from Cuzco, not a town square. Step 5: Note that Catedral de Santo Domingo and Barrio de San Blas refer to a church and a district, respectively. Therefore Plaza de Armas is the correct choice.

Verification / Alternative check:
You can verify by recalling typical tourist itineraries. Visitors to Cuzco often start at Plaza de Armas, where they see the cathedral, colonial arcades, and surrounding hills. From there they may travel to nearby neighbourhoods such as San Blas, or take transport to Machu Picchu on a separate day trip. Guidebooks and maps label the main square clearly as Plaza de Armas, reinforcing its identity as the central plaza.

Why Other Options Are Wrong:
Option B, Machu Picchu, is an ancient Inca citadel located away from the modern city and is not a city square. Option C, Catedral de Santo Domingo, is a notable church that stands on the square but does not name the square itself. Option D, Barrio de San Blas, is a picturesque neighbourhood known for artisans and narrow streets, not the main central plaza. These options describe important places associated with Cuzco but do not answer the question about the name of the main square.

Common Pitfalls:
Students sometimes confuse Machu Picchu with Cuzco and think of them as a single site, leading to the wrong choice. Another pitfall is assuming that the name of a landmark building, such as the cathedral, is the same as the name of the square. To avoid confusion, remember that Plaza de Armas is a generic name found in several colonial cities and is often the correct answer when questions ask for the main square in places like Cuzco and Lima.

Final Answer:
The main central square of Cuzco is called the Plaza de Armas.