Final answer:
South America's most elegant seaside resorts are found in Uruguay with places like Punta del Este, known for its beautiful beaches, urban sophistication, and European influence.
Step-by-step explanation:
One of South America's most elegant seaside resorts is located in Uruguay, known for its high urbanization and tourism appeal. Referencing the context provided, Uruguay's combination of urban sophistication and beachfront amenities make places such as Punta del Este stand out as top destinations for travelers looking for luxury and relaxation. With its beautiful beaches, high-rise apartments, commercial buildings, and active social scene, it rightly earns the reputation of an elegant seaside resort. The region's urbanized setting complements the natural beauty and sophistication of its resorts, mirroring the European influence that characterizes much of the Southern Cone.