Unlike sizzling Rio de Janeiro or seductive Buenos Aires, Santiago comes off as South America’s more straitlaced capital city. Chile, the world’s longest country, stretching almost 2,700 miles from north to south, is packed with plenty of eye-catching landscapes, from the soaring Andes to the arid Atacama Desert. And it’s no wonder that visitors are easily lured away from sleepy Santiago. Many who descend on Chile’s sprawling capital see it simply as a convenient gateway to the country’s real highlights: the Lake District, San Pedro de Atacama, and Torres del Paine National Park in Patagonia.

As Chile’s financial center, Santiago hardly presents a thrill a minute. Its more subdued spirit, however, actually telegraphs the national character, one that still has a bit of a self-esteem issue as it gets beyond its long cultural and geographic isolation. But with a flourishing economy, this city that’s often better-known for its wintertime smog is now in the midst of a building boom. To better understand Santiago’s oft-overlooked architectural treasures and how an influx of wealth is affecting the city’s character, we enlisted the help of architect Sebastián Irarrázaval.

Irarrázaval’s eponymous firm, found in the leafy barrio of Vitacura, has amassed a diverse body of work that includes office buildings, residences, showrooms, and a winery (currently in development), but it’s his ultracool, natural material–driven Indigo Patagonia Hotel that put him on the world design map. He recently won a competition to build the new school of design at the Universidad Católica, where he teaches architecture. In this city, where his father also studied and taught architecture, it’s no wonder Irarrázaval has strong, and not wholly laudatory, opinions about where Santiago is going.

You live in the relative peace of the Vitacura neighborhood. Why stay out of all the action downtown?

Vitacura was one of the first expansions of the city, about 60 years ago. There were cows here at that time. Now, things are changing, with an increase in multistory apartments, art galleries, and shops. But it’s still green. Yes, my house is a few minutes away from my office, but Vitacura is really a neighborhood, which is important because I have five children. Plus, I’m only a 15-minute drive from downtown. And there are many private gardens that you can enjoy, even if you cannot enter them.

Plenty of money is pouring into the capital, but is that necessarily a recipe for desirable growth?

The state has become less powerful and everything is more chaotic. For example, we have plenty of motorways, and that means the centers of the city have lost their importance. In Santiago, you don’t know where the center is. There should be public parts of the city that you could easily recognize, like in Paris and other old cities—which were once models for Santiago. These so-called urban rooms would maintain the same building height, style, and materials on both sides of the street. El Golf was a neighborhood that was planned with “urban rooms” in mind. Now it’s a business district and most of that has been destroyed. Borja Huidobro has been trying to revive this idea of in El Golf, where he did several buildings. And as a result, you can recognize the design of the area.

Is the new construction embracing modernism?

The Chileans associate modernism with prestige, with being forward-looking. It shows the world that Chile is part of a global trend. It’s a way of saying we are not isolated, because Chile had been isolated for so long. Modernism gives freedom to architects; it provides flexibility and plenty of light, and it’s appropriate for the way we now live. Good buildings that are fresh and original can be born here, but, unfortunately, many are just imitations. One of the best pieces of modern architecture in the city, however, is the mountainside chapel Los Benedictinos, by Gabriel Guarda and Martín Correa. With light coming in from skylights and an array of windows, the treatment of light is the main design element. The Palacio de la Moneda, by Joaquín Toesca y Ricci, where [then-president Salvador] Allende died, is one of the best pieces of architecture. Its austere and clear spaces have a sense of permanence. Close to it is the modern Centro Cultural Palacio la Moneda, which I also like. Finally, Rodrigo Pérez de Arce did a nice renovation of Plaza de Armas. He took out half the trees to return the square to a public space, but it also remains a green site for relaxing.

Where do you see a more compelling mix of the old and new?To see old and new buildings in one place, visit the Universidad Católica campus, where I teach. El Comendador is an old colonial house with a green courtyard on the campus. It was once a hacienda and then a hospital. One room is now a studio-workshop; the old stable and chapel are classrooms. It’s like what I do, trying to make things flexible. To be permanent, architecture should be flexible. On campus, there’s also a modernist library that’s unusual because it’s underground and yet has the feeling of being outside. The architect, Teodoro Fernández, has taught at the university for a long time and has won quite a lot of competitions.What sights should not be missed that also provide a window into Santiago life?There is a system of pedestrian passageways, or pasajes, within buildings in downtown Santiago that winds around like a labyrinth. Here, there are odd, independently owned shops selling medical supplies, scissors, and so forth. There are also streets dedicated to one type of product, and this speaks to the city’s handicraft tradition. For example, Calle Victoria is a place where everything leather is sold; Diez de Julio is devoted to car repair and tires; and Baratillo, a narrow passageway, has wicker-furniture stores. I also like shopping at La Vega, a market selling chiles, mushrooms, potatoes, and much more.Where do you recommend a visitor go for shopping or to have a nice meal?In El Golf, Pura is a sophisticated shop with interesting ponchos, scarves, and bags with good handmade traditional designs that have been modernized. Next door is Interdesign, a shop that sells nice furniture and lamps. I also like MAVI (Visual Arts Museum) and the contemporary art exhibitions at Galería Animal. Liguria is a loud and crowded chain restaurant where you can eat rabbit and other types of traditional foods.