Mountains and the sea are an ideal combination—not just for tourists but also for second homes and main homes of people who appreciate the amenities of both types of natural spaces. In the case of the Valparaíso–Viña del Mar agglomeration, the short distance to the Chilean capital, Santiago; access to a World Heritage Site (the city center of Valparaíso); and access to the leisure facilities of Chile's most attractive coastal spa (Viña del Mar) complement the amenities offered by nature. This paper provides information on the dynamic real estate market and the growth of the commercial sector in this agglomeration. It shows that high prices for domiciles with a sea view have led to new urban development farther inland. Thus mountain amenities are becoming more attractive to people moving to the Pacific Coast; however, the ongoing housing development can hardly be considered to correspond to the objectives of sustainable urban development.